We study context-aware time-series forecasting, in which a single target variable is predicted from its own history and a set of contextual variables, such as weather and calendar information. As the context becomes more diverse, a single model struggles to capture all of its regimes, while ensemble learning and Mixture-of-Experts approaches rely on manual data partitioning or soft routing, which increases the inference cost and hinders interpretability. We propose CATF, a Context-Aware Time-Series Forecasting framework built on a Manager-Worker architecture: a Transformer-based Manager routes each input to a single Worker based on the context, using hard routing during both training and inference. The Workers thus specialize without manual data partitioning, and any single-model forecaster can serve as a Worker. On five context-rich datasets, four horizons, and two normalization schemes, CATF improves over its standalone counterpart in 162 of 200 comparisons, the best CATF-enhanced model outperforms the best standalone baseline in 19 of 20 settings, and it outperforms the zero-shot Time-MoE foundation model in 15 of 20 settings. A case study on bike-sharing data shows that the Manager routes inputs by the calendar and that each Worker specializes in a different weekly pattern.
Figures & tables
Figure 1. Manager–Worker architecture of CATF . (a) Given the target history X and the context history C , the manager M outputs routing probabilities P^ over the K workers. The worker with the highest probability, Wk∗ , receives the same input (X,C) and alone predicts the future target sequence Y^ . (b) Inside the manager: feature encoding (L1), Lm Transformer encoder layers (L2), last-timestep pooling, a decoder (L3), and softmax (L4). Two-panel architecture diagram. The upper panel shows the target history and the context history entering a manager that selects one worker by the largest routing probability. The same historical input is passed directly to that worker, which alone produces the target forecast. The lower panel expands the manager into feature encoding, Transformer encoders, last-timestep pooling, decoder, and softmax.
Figure 2. Iterative training of CATF , illustrated for one sample. (a) All workers first produce forecasts and losses (steps 1–2). (b) Their losses and training volumes define a pseudo target (step 3) that supervises the manager update (step 4). (c) The updated manager then selects one worker (step 5), and only that worker is trained on the sample (step 6). Three-phase training diagram with six chronological steps. All workers first predict and are scored against the target. Worker losses and training volumes define a pseudo target that supervises the manager. The updated manager then selects one worker for the sample, and only that worker receives a forecasting update. A return arrow repeats the process with updated workers and training volumes.
Dataset
Ly
iTransformer ( ( 2024a ) )
TimesNet ( ( 2023a ) )
FEDformer ( ( 2022 ) )
Autoformer ( ( 2021 ) )
Informer ( ( 2021 ) )
Global
Sample
Global
Sample
Global
Sample
Global
Sample
Global
Sample
Base
+ CATF
Base
+ CATF
Base
+ CATF
Base
+ CATF
Base
+ CATF
Base
+ CATF
Base
+ CATF
Base
+ CATF
Base
+ CATF
Base
+ CATF
Weather
96
204.7
194.9
447.0
178.3
245.6
215.9
418.6
158.5
28,741
351.3
1,208,418
181.7
39,860
419.5
1,933,907
210.1
1,733
442.7
4,402
155.7
192
249.3
226.7
637.6
231.6
271.1
234.8
410.6
226.1
28,712
548.9
10,628,690
236.8
230,293
380.4
151,937
285.4
6,645
426.5
7,309
220.8
336
254.6
232.3
749.2
254.8
264.8
243.3
456.7
241.8
50,859
559.7
380,781
267.3
70,468
279.8
157,994
270.1
77,472
460.2
3,729
240.1
720
270.1
235.9
748.3
330.0
269.1
241.7
963.3
291.8
41,001
640.8
798,364
268.3
209,899
259.7
29,367
296.1
4,335
527.5
3,637
290.7
Table 1. Forecasting results (MSE on the original scale, mean over 5 runs) of each baseline (Base) and its CATF -enhanced version (+ CATF ) under global and sample normalization; look-back length L=96 . The better of each baseline and its CATF -enhanced version is in bold ; the best result in each row is marked with a dark orange background and the second best with a light orange background. CATF Win: number of the 20 settings (5 datasets × 4 horizons) in which CATF - < baseline > has a lower mean MSE than < baseline > . Impr.: relative MSE reduction of CATF - < baseline > over < baseline > , averaged over the 20 settings. The very large MSE of some baselines on Weather is caused by missing-value codes in the training target (Appendix B.6 ). Mean ± SD for every setting is listed in Appendix Tables 9 and 10 .
Dataset
Ly
Best baseline
Best CATF -enhanced
Time-MoE ( ( 2025 ) )
Model
MSE
Model
MSE
MSE
Weather
96
iTransformer
204.7 G
CATF -Informer
155.7 S
164.9 S
192
iTransformer
249.3 G
CATF -Informer
220.8 S
215.0 S
336
iTransformer
254.6 G
CATF -iTransformer
232.3 G
225.6 S
720
TimesNet
269.1 G
CATF -iTransformer
235.9 G
233.5 S
PM2.5-LA
96
iTransformer
36.08 S
CATF -iTransformer
35.20 S
39.66 S
Table 2. Best standalone baseline vs. best CATF -enhanced model vs. zero-shot Time-MoE ( Shi et al., 2025 ) . For each setting, the best baseline (best CATF -enhanced model) is the lowest mean MSE over the five baselines ( CATF -enhanced models) and the two normalization schemes; for Time-MoE (single deterministic run), the better of the two normalization schemes is used. The superscript gives the normalization (G: global, S: sample). The best result in each row is in bold with a light orange background. CATF Win: number of the 20 settings in which the best CATF -enhanced model has a lower MSE than the best baseline (Time-MoE); Impr.: relative MSE reduction of the best CATF -enhanced model over the best baseline (Time-MoE), averaged over the 20 settings.
Setting
MSE
Δ (%)
p
Default
80.52 ± 1.02
–
–
Loss
KL only
81.87 ± 2.75
+1.7
0.347
Wasserstein only
81.56 ± 1.10
+1.3
0.157
Reg.
No reg.
80.94 ± 1.19
+0.5
0.559
Manager
Small ( dmodel=128 )
81.23 ± 0.78
+0.9
0.252
Large ( dmodel=768 )
81.05 ± 0.81
+0.7
0.386
Table 3. Ablation study of CATF -iTransformer on PM2.5-RV (global normalization, L=Ly=96 ). MSE is mean ± SD over 5 runs without fixed random seeds; the default setting is an independent re-run of the configuration in Table 1 (MSE 81.07±1.18 there). Δ is the relative change in mean MSE w.r.t. the default (positive is worse); p is from Welch’s t -test against the default (bold: p<0.05 ). The results on Bike Share are reported in Appendix Table 17 .
Figure 3. Routing of CATF -iTransformer on Bike Share (mean over 5 runs). (a) Test MSE of the same trained workers under the learned routing, the best single worker for all samples, an untrained manager, and random routing with the same worker shares. (b) Share of routing decisions that change when one variable is shuffled across test samples in the manager input only (top 8 of 12 inputs; “All context” shuffles all context variables at once), for the trained and an untrained manager. (c) MSE of each worker on the samples routed to each worker, divided by the lowest MSE in the row and averaged over runs.
Figure 4. What each worker of CATF -iTransformer handles on Bike Share (one run). (a) Share of the forecasts made on each day of the week that are routed to each worker. (b) Mean bike rentals in the 96-hour forecast window for the forecasts made at midnight, grouped by the selected worker. W1 handles the forecasts made on Sunday to Tuesday, whose window consists mostly of working days (29 forecasts, on average 3.4 working days in the window); W2 handles the forecasts made on Wednesday to Friday, whose window reaches into the weekend (29 forecasts, 2.3 working days); W3 handles the forecasts made on Friday and Saturday, whose window starts with the weekend (11 forecasts, 1.9 working days).
Appendix figures & tables22 assets
Supplementary material from the paper’s appendix.
Appendix
Dataset
#Variables
Target
Input Length ( L )
Output Length ( Ly )
Frequency
Dataset Size
Domain
Weather
21
CO 2 (ppm)
96
{96, 192, 336, 720}
10 minutes
52,696
Meteorology
PM2.5-LA
15
PM2.5 ( μ g/m 3 )
96
{96, 192, 336, 720}
1 hour
35,063
Air quality
PM2.5-RV
15
PM2.5 ( μ g/m 3 )
96
{96, 192, 336, 720}
1 hour
35,063
Air quality
Bike Share
12
Rental count
96
{96, 192, 336, 720}
1 hour
17,379
Transportation
Appliances
26
Energy use (Wh)
96
{96, 192, 336, 720}
10 minutes
19,735
Energy
Appendix
Table 4. Statistics of the datasets used in the forecasting tasks. #Variables counts all numeric columns, including the target. Dataset Size is the number of time steps.
Model
#Layers
#Model Dimension
#Feedforward Dimension
#Attention Heads
#Dropout
#Attention Factor
#Learning Rate
i-Transformer
2
128
128
8
0.1
3
0.0001
TimesNet
2
32
32
8
0.1
3
0.0001
FEDformer
2
512
2048
8
0.1
3
0.0001
Autoformer
2
512
2048
8
0.1
3
0.0001
Informer
2
512
2048
8
0.1
3
0.0001
Appendix
Table 5. Summary of worker models and baselines’ hyperparameters used in our CATF framework.
Model Type
#Layers
#Model Dimension
#Feedforward Dimension
#Attention Heads
#Dropout
Transformer
2
512
2048
8
0.05
Appendix
Table 6. Default setting of the manager model hyperparameter that is used in our CATF framework.
Model
Manager LR
Worker LR
CATF-iTransformer
0.00001
0.0001
CATF-TimesNet
0.00001
0.0001
CATF-FEDformer
0.001
0.0001
CATF-Autoformer
0.00001
0.0001
CATF-Informer
0.00001
0.0001
Appendix
Table 7. Learning rates of the manager and worker models in CATF -enhanced models (identical for all datasets). Both are optimized with Adam and a weight decay of 10−5 .
Hyperparameter
Baseline
CATF Models
Shared Settings
Batch Size
32
32
Training Size
0.8
0.8
Validation Size
0.1
0.1
Test Size
0.1
0.1
Epochs
10
30
Appendix
Table 8. Training hyperparameters for CATF and Baseline models.
Dataset
Ly
iTransformer ( ( 2024a ) )
CATF - iTransformer
TimesNet ( ( 2023a ) )
CATF - TimesNet
FEDformer ( ( 2022 ) )
CATF - FEDformer
Autoformer ( ( 2021 ) )
CATF - Autoformer
Informer ( ( 2021 ) )
CATF - Informer
Weather
96
204.7 ± 2.29
194.9 ± 5.19
245.6 ± 10.69
215.9 ± 21.53
28,741 ± 16,160
351.3 ± 97.78
39,860 ± 35,693
419.5 ± 104.1
1,733 ± 830.7
442.7 ± 35.52
192
249.3 ± 3.11
226.7 ± 8.12
271.1 ± 13.23
234.8 ± 8.91
28,712 ± 19,726
548.9 ± 19.67
230,293 ± 340,357
380.4 ± 53.86
6,645 ± 10,171
426.5 ± 44.44
336
254.6 ± 2.15
232.3 ± 3.39
264.8 ± 3.40
243.3 ± 6.20
50,859 ± 39,591
559.7 ± 79.00
70,468 ± 97,935
279.8 ± 13.24
77,472 ± 170,210
460.2 ± 41.99
720
270.1 ± 2.85
235.9 ± 6.54
269.1 ± 5.97
241.7 ± 4.23
41,001 ± 22,172
640.8 ± 66.33
209,899 ± 267,336
259.7 ± 12.00
4,335 ± 4,652
527.5 ± 59.48
PM2.5-LA
96
37.05 ± 0.39
37.02 ± 0.28
37.32 ± 1.68
44.42 ± 3.64
57.75 ± 4.31
42.29 ± 1.29
86.25 ± 24.26
71.18 ± 6.13
45.34 ± 4.37
45.04 ± 6.22
192
40.64 ± 0.30
41.17 ± 0.24
40.16 ± 1.94
42.52 ± 2.36
65.63 ± 1.73
45.25 ± 0.86
66.43 ± 8.03
64.94 ± 4.65
46.80 ± 3.08
42.66 ± 0.25
Appendix
Table 9. Long-term forecasting results under Global normalization. MSE is computed on the original (de-normalized) scale and reported as MEAN ± SD over 5 runs. The look-back length is 96 for all settings. The better of each baseline and its CATF -enhanced version is in bold ; the best result in each row is marked with a dark orange background and the second best with a light orange background. CATF Win: number of the 20 settings (5 datasets × 4 horizons) in which CATF - < baseline > has a lower mean MSE than < baseline > . Impr.: relative MSE reduction of CATF - < baseline > over < baseline > , averaged over the 20 settings.
Dataset
Ly
iTransformer ( ( 2024a ) )
CATF - iTransformer
TimesNet ( ( 2023a ) )
CATF - TimesNet
FEDformer ( ( 2022 ) )
CATF - FEDformer
Autoformer ( ( 2021 ) )
CATF - Autoformer
Informer ( ( 2021 ) )
CATF - Informer
Weather
96
447.0 ± 47.15
178.3 ± 9.00
418.6 ± 150.0
158.5 ± 10.52
1,208,418 ± 1,398,675
181.7 ± 6.57
1,933,907 ± 1,800,987
210.1 ± 24.66
4,402 ± 3,262
155.7 ± 6.54
192
637.6 ± 71.19
231.6 ± 4.39
410.6 ± 120.8
226.1 ± 6.49
10,628,690 ± 15,360,229
236.8 ± 9.04
151,937 ± 325,720
285.4 ± 31.47
7,309 ± 2,449
220.8 ± 15.75
336
749.2 ± 64.09
254.8 ± 8.98
456.7 ± 167.3
241.8 ± 6.77
380,781 ± 420,438
267.3 ± 16.56
157,994 ± 251,704
270.1 ± 12.01
3,729 ± 1,411
240.1 ± 5.54
720
748.3 ± 46.15
330.0 ± 35.88
963.3 ± 360.3
291.8 ± 17.00
798,364 ± 652,673
268.3 ± 18.87
29,367 ± 28,419
296.1 ± 33.97
3,637 ± 1,223
290.7 ± 16.44
PM2.5-LA
96
36.08 ± 0.96
35.20 ± 0.96
40.18 ± 4.20
35.43 ± 1.30
60.91 ± 9.88
42.11 ± 2.02
57.60 ± 6.91
58.89 ± 3.52
41.30 ± 2.24
37.90 ± 1.28
192
40.93 ± 0.48
40.81 ± 0.46
42.62 ± 3.67
39.25 ± 1.73
64.07 ± 2.94
43.77 ± 1.81
61.37 ± 14.40
65.62 ± 8.96
42.06 ± 1.10
39.62 ± 0.90
Appendix
Table 10. Long-term forecasting results under Sample normalization. MSE is computed on the original (de-normalized) scale and reported as MEAN ± SD over 5 runs. The look-back length is 96 for all settings. The better of each baseline and its CATF -enhanced version is in bold ; the best result in each row is marked with a dark orange background and the second best with a light orange background. CATF Win: number of the 20 settings (5 datasets × 4 horizons) in which CATF - < baseline > has a lower mean MSE than < baseline > . Impr.: relative MSE reduction of CATF - < baseline > over < baseline > , averaged over the 20 settings.
Dataset
Ly
iTransformer
TimesNet
FEDformer
Autoformer
Informer
G
S
G
S
G
S
G
S
G
S
Weather
96
+4.8
+60.1
+12.1
+62.1
+98.8
+100.0
+98.9
+100.0
+74.5
+96.5
192
+9.1
+63.7
+13.4
+44.9
+98.1
+100.0
+99.8
+99.8
+93.6
+97.0
336
+8.7
+66.0
+8.1
+47.1
+98.9
+99.9
+99.6
+99.8
+99.4
+93.6
720
+12.7
+55.9
+10.2
+69.7
+98.4
+100.0
+99.9
+99.0
+87.8
+92.0
PM2.5-LA
96
+0.1
+2.4
-19.0
+11.8
+26.8
+30.9
+17.5
-2.3
+0.7
+8.2
Appendix
Table 11. MSE reduction (%) of CATF - < baseline > over < baseline > , computed on the mean MSE over 5 runs as (baseline − CATF )/baseline. Positive values mean CATF is better. G = global normalization, S = sample normalization. Significance is tested with a two-sided Welch’s t -test over the 5 runs of each model: bold = CATF is significantly better ( p<0.05 ), underlined = CATF is significantly worse ( p<0.05 ).
Dataset
Ly
( Liu et al., 2024a ) iTransformer
CATF - iTransformer
( Wu et al., 2023a ) TimesNet
CATF - TimesNet
( Zhou et al., 2022 ) FEDformer
CATF - FEDformer
( Wu et al., 2021 ) Autoformer
CATF - Autoformer
( Zhou et al., 2021 ) Informer
CATF - Informer
TimeMoE (zero-shot)
Weather
96
10.31 ± 0.07
10.05 ± 0.16
11.41 ± 0.25
10.23 ± 0.49
133.1 ± 42.16
14.26 ± 1.53
154.9 ± 88.36
15.97 ± 2.15
32.48 ± 8.31
16.52 ± 0.83
21.61
192
11.64 ± 0.07
11.04 ± 0.17
12.16 ± 0.27
11.30 ± 0.17
133.1 ± 64.82
18.50 ± 0.29
241.3 ± 233.3
14.93 ± 1.06
32.27 ± 12.88
15.93 ± 1.12
24.60
336
12.03 ± 0.05
11.43 ± 0.11
12.25 ± 0.08
11.72 ± 0.10
195.6 ± 75.97
18.37 ± 1.31
150.0 ± 121.0
12.79 ± 0.34
46.55 ± 63.01
16.70 ± 0.97
26.44
720
12.71 ± 0.08
11.74 ± 0.20
12.64 ± 0.17
11.92 ± 0.11
174.9 ± 58.48
20.08 ± 1.08
274.6 ± 233.7
12.26 ± 0.26
34.14 ± 6.19
18.16 ± 1.20
28.63
PM2.5-LA
96
3.91 ± 0.01
3.93 ± 0.00
3.91 ± 0.06
4.13 ± 0.19
5.77 ± 0.24
4.72 ± 0.07
6.80 ± 1.00
6.27 ± 0.26
5.07 ± 0.26
4.97 ± 0.22
4.41
192
4.20 ± 0.02
4.24 ± 0.02
4.18 ± 0.09
4.24 ± 0.09
6.19 ± 0.09
4.88 ± 0.05
6.02 ± 0.39
5.99 ± 0.22
5.21 ± 0.14
4.96 ± 0.05
4.92
Appendix
Table 12. Long-term forecasting results under Global normalization. MAE is computed on the original (de-normalized) scale and reported as MEAN ± SD over 5 runs (TimeMoE: single zero-shot run). The look-back length is 96 for all settings. The better of each baseline and its CATF -enhanced version is in bold ; the best result in each row is marked with a dark orange background and the second best with a light orange background. CATF Win: number of the 20 settings (5 datasets × 4 horizons) in which CATF -<baseline> has a lower mean MAE than <baseline>. Impr.: relative MAE reduction of CATF -<baseline> over <baseline>, averaged over the 20 settings.
Dataset
Ly
( Liu et al., 2024a ) iTransformer
CATF - iTransformer
( Wu et al., 2023a ) TimesNet
CATF - TimesNet
( Zhou et al., 2022 ) FEDformer
CATF - FEDformer
( Wu et al., 2021 ) Autoformer
CATF - Autoformer
( Zhou et al., 2021 ) Informer
CATF - Informer
TimeMoE (zero-shot)
Weather
96
14.13 ± 0.67
9.28 ± 0.20
11.84 ± 0.57
8.61 ± 0.25
725.8 ± 476.1
9.45 ± 0.19
983.5 ± 593.3
10.04 ± 0.43
28.87 ± 8.79
8.53 ± 0.20
9.05
192
17.43 ± 1.09
10.89 ± 0.12
12.80 ± 0.83
10.71 ± 0.10
1,691 ± 2,008
11.22 ± 0.19
185.3 ± 305.8
12.06 ± 0.46
32.24 ± 6.16
10.65 ± 0.25
10.63
336
19.16 ± 0.73
11.76 ± 0.17
13.89 ± 1.76
11.44 ± 0.19
380.7 ± 239.9
12.32 ± 0.37
194.7 ± 123.2
12.12 ± 0.22
29.58 ± 7.54
11.47 ± 0.10
11.14
720
19.89 ± 0.54
13.34 ± 0.57
17.53 ± 2.17
12.36 ± 0.35
588.6 ± 274.4
12.52 ± 0.49
118.6 ± 83.34
13.18 ± 0.89
28.66 ± 4.30
12.62 ± 0.35
11.55
PM2.5-LA
96
3.93 ± 0.06
3.87 ± 0.07
4.02 ± 0.12
3.85 ± 0.06
5.21 ± 0.46
4.24 ± 0.12
4.89 ± 0.24
5.07 ± 0.20
4.33 ± 0.18
4.12 ± 0.10
4.10
192
4.25 ± 0.04
4.26 ± 0.03
4.26 ± 0.15
4.14 ± 0.06
5.45 ± 0.10
4.39 ± 0.12
5.13 ± 0.48
5.37 ± 0.31
4.40 ± 0.07
4.26 ± 0.07
4.41
Appendix
Table 13. Long-term forecasting results under Sample normalization. MAE is computed on the original (de-normalized) scale and reported as MEAN ± SD over 5 runs (TimeMoE: single zero-shot run). The look-back length is 96 for all settings. The better of each baseline and its CATF -enhanced version is in bold ; the best result in each row is marked with a dark orange background and the second best with a light orange background. CATF Win: number of the 20 settings (5 datasets × 4 horizons) in which CATF -<baseline> has a lower mean MAE than <baseline>. Impr.: relative MAE reduction of CATF -<baseline> over <baseline>, averaged over the 20 settings.
Model
Weather
PM2.5-LA
PM2.5-RV
Bike Share
Appliances
#Global better
Median (all)
iTransformer
+166
+0.5
−1.5
−2.1
+97
11/20
+0.5
TimesNet
+71
+3.6
+1.5
−5.7
+112
13/20
+6.9
FEDformer
+2,976
+5.7
+0.4
+52
+249
17/20
+52
Autoformer
+45
−3.6
+3.5
+11
+471
14/20
+14
Informer
−3.1
+0.3
+3.5
−0.1
+405
14/20
+5.5
CATF -iTransformer
+5.9
−0.7
−1.3
−1.4
+35
9/20
−0.4
Appendix
Table 14. Global vs. sample normalization. For each model and dataset, the cell is the median over the four horizons of the relative difference in mean MSE, (sample − global)/global (%); positive values mean that global normalization is better. The last two columns give the number of the 20 settings (5 datasets × 4 horizons) in which global normalization is better, and the median relative difference over all 20 settings.
iTransformer
TimesNet
FEDformer
Autoformer
Informer
Dataset
Ly
Base
CATF
Base
CATF
Base
CATF
Base
CATF
Base
CATF
Weather
96
204.7 G
178.3 S
245.6 G
158.5 S
28,741 G
181.7 S
39,860 G
210.1 S
1,733 G
155.7 S
192
249.3 G
226.7 G
271.1 G
226.1 S
28,712 G
236.8 S
151,937 S
285.4 S
6,645 G
220.8 S
336
254.6 G
232.3 G
264.8 G
241.8 S
50,859 G
267.3 S
70,468 G
270.1 S
3,729 S
240.1 S
720
270.1 G
235.9 G
269.1 G
241.7 G
41,001 G
268.3 S
29,367 S
259.7 G
3,637 S
290.7 S
PM2.5-LA
96
36.08 S
35.20 S
37.32 G
35.43 S
57.75 G
42.11 S
57.60 S
58.89 S
41.30 S
37.90 S
Appendix
Table 15. Best normalization per model. For each model, we take the lower mean MSE of global (G) and sample (S) normalization (Tables 9 and 10 ), separately for the standalone baseline (Base) and its CATF -enhanced version; the superscript gives the selected normalization. Bold marks the better of each baseline and its CATF -enhanced version. CATF Win: number of the 20 settings in which CATF improves over its baseline; Impr.: relative MSE reduction (%), averaged over the 20 settings.
Ly=96
Ly=192
Ly=336
Ly=720
Model
Time (s/ep.)
Mem. (GB)
Time (s/ep.)
Mem. (GB)
Time (s/ep.)
Mem. (GB)
Time (s/ep.)
Mem. (GB)
Epochs
iTransformer
17
0.04
19
0.04
33
0.09
23
0.05
7.1
CATF -iTransformer
283
0.46
239
0.46
398
0.48
250
0.48
26.7
TimesNet
76
0.13
95
0.15
728
0.20
205
0.29
7.0
CATF -TimesNet
725
0.57
559
0.65
2,227
0.79
922
1.00
26.1
FEDformer
301
1.62
329
1.78
1,443
2.07
499
2.68
6.7
Appendix
Table 16. Computational cost of the baselines and CATF -enhanced models (3 workers): training time per epoch (s), peak GPU memory during training (GB), and the average number of trained epochs, for each forecasting horizon Ly . Values are averaged over the 5 datasets, 2 normalization schemes, and 5 runs. Several runs shared one GPU, so the times are indicative. For the zero-shot Time-MoE (50M), we report the total inference time on the test split and the peak memory.
Bike Share
PM2.5-RV
Setting
MSE
MAE
Δ (%)
p
MSE
MAE
Δ (%)
p
#Params (M)
Default (KL + Wass., reg., dmodel=512 , K=3 )
15,097 ± 241
78.56 ± 0.67
–
–
80.52 ± 1.02
6.18 ± 0.03
–
–
7.3
Manager loss
KL only
15,452 ± 282
79.36 ± 0.71
+2.4
0.065
81.87 ± 2.75
6.15 ± 0.03
+1.7
0.347
7.3
Wasserstein only
15,407 ± 372
80.48 ± 0.83
+2.1
0.163
81.56 ± 1.10
6.21 ± 0.04
+1.3
0.157
7.3
Regularization
No reg.
15,169 ± 184
79.01 ± 0.40
+0.5
0.609
80.94 ± 1.19
6.14 ± 0.03
+0.5
0.559
7.3
Manager arch.
Small ( dmodel=128 , dff=512 , 4 heads)
15,155 ± 298
79.32 ± 0.77
+0.4
0.743
81.23 ± 0.78
6.19 ± 0.04
+0.9
0.252
1.1
Appendix
Table 17. Full ablation results of CATF -iTransformer on Bike Share and PM2.5-RV (global normalization, L=Ly=96 ). MSE and MAE are on the original scale, mean ± SD over 5 runs without fixed random seeds. Δ is the relative change in mean MSE w.r.t. the default setting of the same dataset (positive is worse); p is from Welch’s t -test against the default (bold: p<0.05 ). #Params counts the manager and all workers on Bike Share.
Figure 5. Routing on synthetic data over the first 600 test steps (one run). Top: target series. Middle: true regime of the forecast window. Bottom: worker selected by the manager. The selected worker follows the regime switches; the agreement is 99.4% over the whole test set.
Figure 6. Routing on synthetic data, averaged over 3 runs. (a) Share of the samples of each true regime that the trained manager routes to each worker. (b) The same for an untrained manager with the same architecture and the same trained workers. (c) MSE of each worker on each regime. (d) Permutation importance: share of routing decisions that change when one input variable is shuffled across test samples in the manager input only (workers receive the original input), for the trained and the untrained manager. Workers are relabeled in each run so that Wk is the worker that receives regime k most often.
Model / routing
MSE
NMI
iTransformer (baseline)
35.98 ± 0.34
–
CATF -iTransformer
33.39 ± 0.51
0.85 ± 0.15
Same trained workers, different routing
Random routing (same worker shares)
50.69 ± 4.18
–
Best single worker for all samples
43.77 ± 1.76
–
Untrained manager
58.13 ± 6.06
0.04 ± 0.04
Appendix
Table 18. Synthetic data ( L=Ly=96 , global normalization, 3 runs, mean ± SD). The routing variants reuse the trained workers and change only the routing. NMI: between the routing and the true regime.
Figure 7. Counterfactual analysis of the routing of CATF -iTransformer on Bike Share (mean over 5 runs). For each shift d , either the calendar of the input window (day of the week and working-day indicator) is shifted by d days (blue) or the target history is replaced with that of the forecast made d days later (orange), with all other inputs unchanged. (a) Percentage of test forecasts whose selected worker differs from the one selected for the original input. (b) Percentage of test forecasts whose selected worker is the typical worker of the new day, i.e., the majority worker of the real forecasts made d days later at the same hour; the dashed line is this percentage for the original input before any change.
Figure 8. Routing of CATF -iTransformer on Bike Share over four weeks of the test period (one run). Top: hourly bike rentals, with weekends in gray and holidays in red. Bottom: the worker selected for the forecast that starts at each hour. The routing follows the weekly cycle: W1 for forecasts made on Sunday to Tuesday, W2 for Wednesday to Friday, and W3 for Friday and Saturday. Thanksgiving (Thursday, Nov 22) is routed to W3 , like a Saturday.
Figure 9. Context conditions of the Bike Share test samples routed to each worker (one run; the same run as Figure 8 ). Each line is the mean over the samples routed to a worker at each hour relative to the forecast origin (dashed: all samples); the gray area is the forecast window, which the manager does not see. Rentals are shown as a trailing 24-hour mean. The workers correspond to different phases of the week (working-day share) and therefore to different demand trajectories, whereas the weather conditions are similar for all workers.
Figure 10. Routing of the Bike Share test forecasts by each input variable (one run; the same run as Figure 9 ). The variables are taken at the forecast origin; continuous variables are split into tertiles over the test period, and the number of forecasts in each bin is given in parentheses. Each row gives the percentage of the forecasts in the bin that are routed to each worker (rows sum to 100%; first row: all forecasts). Left: day of the week, working day, holiday, and month; right: weather and recent demand. The column “Variable (NMI)” gives the variable of each group of rows and, in parentheses, the normalized mutual information (NMI) between its bin and the selected worker (0: unrelated; 1: the bin determines the worker). The routing depends strongly on the day of the week and the working-day indicator, and only weakly on the other variables.
Figure 11. Example forecasts on Bike Share for typical forecast origins of each worker (one run; the same run as Figure 8 ), together with the standalone iTransformer. For each case, the forecast with the median CATF error among all forecasts starting at midnight on that day of the week (without holidays in the forecast window) is shown. The gray area is the forecast window. The largest difference occurs for the forecast starting on Saturday, for which W3 captures the midday weekend peak that the standalone iTransformer underestimates.
Time series forecasting predicts future values from ordered observations using statistical, neural, and probabilistic models to support decisions under uncertainty.
Time series forecasting is fundamental to decision-making in complex systems, where future dynamics are influenced not only by historical observations but also by evolving contextual features. Recent advances in large language models (LLMs) have extended forecasting beyond numerical extrapolation toward context-aware reasoning. However, existing approaches often lack explicit mechanisms to identify relevant contexts, reason about their impacts, and validate forecasts against temporal and domain constraints. In this work, we propose CastFSR, an agentic framework that formulates context-aware forecasting as a Fast--Slow--Reflect workflow. In fast thinking, CastFSR profiles observations and selects lightweight forecasters to construct a data-driven forecast prior. In slow deliberation, it retrieves contextual evidence, adaptively determines informative look-back windows, and reasons about how contexts reshape future dynamics. In reflection, it iteratively refines forecasts to ensure temporal, contextual, and domain consistency. CastFSR supports both training-free inference with off-the-shelf LLMs and efficient deployment through a two-stage SFT and reinforcement learning strategy that transfers its orchestration capability to compact LLMs. Extensive experiments on public datasets demonstrate that CastFSR consistently outperforms representative baselines. Our code is available at https://github.com/Xiaoyu-Tao/CastFSR.
Xiaoyu Tao, Mingyue Cheng, Bokai Pan +6
State Key Laboratory of Cognitive Intelligence, University of Science and Technology of China, Hefei, Anhui Province, China
Real-world time-series applications increasingly require models that can handle time series forecasting, context-conditioned prediction, and language-based temporal reasoning. Yet current time-series foundation models remain fragmented across these capabilities: numerical specialists often provide the strongest forecasts, while language-based models offer broader contextual understanding and analysis. A central challenge is to unify these heterogeneous capabilities without reducing their individual performance. We introduce OpenTSLM TeeMoE, a generalist time-series language model that can forecast directly from observed time series, reason over textual context and temporal patterns, and synthesize and refine predictions from external numerical forecasting specialists. We independently train three low-rank experts for forecast aggregation, native forecasting, and temporal analysis over a shared backbone. A learned LoRA mixture-of-experts controller then weights their frozen parameter updates for each request. Our proposed model achieves strong performance on widely used benchmarks for time series forecasting, context-conditioned prediction, and language-based temporal reasoning, ranking among the top three on GIFT-Eval by mean MASE rank, Context is Key by RCRPS, and TimeSeriesExam by accuracy.
Tony Chen, Timo Stoffregen, Maxwell Xu +8
Columbia University, USA · Stanford University, USA · Aionic Labs, Switzerland +4
Time series forecasting models are increasingly scaled through large Transformer backbones, yet most existing approaches process all series through a shared dense computation path despite substantial heterogeneity in temporal structure. Mixture-of-Experts (MoE) offers a natural alternative by enabling conditional computation, but standard MoE routing leaves expert specialization weakly identified and often unstable during downstream adaptation. We propose AME-TS, a structure-guided sparse time series foundation model that aligns expert routing with interpretable temporal structure. AME-TS first uses a lightweight regime predictor to estimate series-level descriptors, including forecastability, seasonality, trend, and sparsity, and maps them to a soft structural prior over experts. This series-level prior guides token-level routing during training, encouraging structure-aligned specialization. On the GIFT-Eval benchmark, AME-TS delivers a strong accuracy-efficiency tradeoff across model scales: it substantially outperforms existing time series foundation models at small model scales and remains competitive with the strongest models at larger scales, while activating substantially fewer parameters through sparse routing. We further show that AME-TS learns more interpretable routing geometry and substantially more stable expert specialization than standard MoE during fine-tuning on the M5 dataset. These results suggest that structure-aware routing is an effective and reliable way to realize the benefits of sparse expert models for time series forecasting.