WALC Demand Forecast Accuracy: Error, Bias and Worst Miss, 6 October to 5 November 2026
The day-ahead demand forecast for WALC was off by 17.0% on average (mean absolute percentage error) over 719 hours from 6 October to 5 November 2026, and 20% of hours landed within 5% of the reading. Its bias was +8.9%: it ran high on average, an over forecast. The largest miss was 801 MW (120.6%) too high at 2 Nov 2026, 15:00 MST (UTC-07:00). Dates and times are local (America/Phoenix).
Key Facts
- The day-ahead demand forecast for WALC was off by 17.0% on average (mean absolute percentage error) over 719 hours from 6 October to 5 November 2026, and 20% of hours landed within 5% of the reading. Its bias was +8.9%: it ran high on average, an over forecast. The largest miss was 801 MW (120.6%) too high at 2 Nov 2026, 15:00 MST (UTC-07:00).
- Across 53 US grids ranked by average error over their own latest 30 day windows, WALC came 47 (1 is the smallest error).
- On average the forecast differed from reported demand by 131 MW, against average demand of 829 MW.
- The forecast was above reported demand in 62% of compared hours.
Forecast Error at a Glance
719 hours from 6 October to 5 November 2026Average error17.0%
Bias+8.9%
Hours within 5%20%
Worst miss801 MW
Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+54 MW per hour on average): the forecast ran high on average, an over forecast. The worst miss was 801 MW (120.6%) too high at 2 Nov 2026, 15:00 MST (UTC-07:00): forecast 1,465 MW, reported 664 MW.
Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) Data as of 2026-11-05. Accuracy is computed by World Power Monitor from the operator's hourly forecast and reported demand.
Forecast and Reported Demand, Last 7 Days
Local time, to 5 Nov 2026, 06:00 MST (UTC-07:00)Data to 2026-11-05
Show the data table (168 rows)
| Local hour | Reported demand | Day-ahead forecast |
|---|---|---|
| 29 Oct, 07:00 | 576 MW | 808 MW |
| 29 Oct, 08:00 | 840 MW | 1,019 MW |
| 29 Oct, 09:00 | 819 MW | 1,059 MW |
| 29 Oct, 10:00 | 859 MW | 1,019 MW |
| 29 Oct, 11:00 | 872 MW | 1,015 MW |
| 29 Oct, 12:00 | 820 MW | 1,065 MW |
| 29 Oct, 13:00 | 841 MW | 1,064 MW |
| 29 Oct, 14:00 | 826 MW | 1,054 MW |
| 29 Oct, 15:00 | 855 MW | 1,069 MW |
| 29 Oct, 16:00 | 806 MW | 988 MW |
| 29 Oct, 17:00 | 795 MW | 1,141 MW |
| 29 Oct, 18:00 | 873 MW | 1,125 MW |
| 29 Oct, 19:00 | 868 MW | 1,160 MW |
| 29 Oct, 20:00 | 920 MW | 925 MW |
| 29 Oct, 21:00 | 935 MW | 853 MW |
| 29 Oct, 22:00 | 915 MW | 904 MW |
| 29 Oct, 23:00 | 763 MW | 700 MW |
| 30 Oct, 00:00 | 676 MW | 706 MW |
| 30 Oct, 01:00 | 634 MW | 771 MW |
| 30 Oct, 02:00 | 643 MW | 715 MW |
| 30 Oct, 03:00 | 628 MW | 687 MW |
| 30 Oct, 04:00 | 650 MW | 682 MW |
| 30 Oct, 05:00 | 646 MW | 745 MW |
| 30 Oct, 06:00 | 896 MW | 678 MW |
| 30 Oct, 07:00 | 704 MW | 666 MW |
| 30 Oct, 08:00 | 868 MW | 723 MW |
| 30 Oct, 09:00 | 924 MW | 754 MW |
| 30 Oct, 10:00 | 922 MW | 756 MW |
| 30 Oct, 11:00 | 993 MW | 803 MW |
| 30 Oct, 12:00 | 988 MW | 848 MW |
| 30 Oct, 13:00 | 1,011 MW | 868 MW |
| 30 Oct, 14:00 | 987 MW | 866 MW |
| 30 Oct, 15:00 | 988 MW | 817 MW |
| 30 Oct, 16:00 | 796 MW | 789 MW |
| 30 Oct, 17:00 | 775 MW | 1,013 MW |
| 30 Oct, 18:00 | 887 MW | 1,072 MW |
| 30 Oct, 19:00 | 946 MW | 1,046 MW |
| 30 Oct, 20:00 | 891 MW | 1,070 MW |
| 30 Oct, 21:00 | 814 MW | 849 MW |
| 30 Oct, 22:00 | 674 MW | 823 MW |
| 30 Oct, 23:00 | 613 MW | 705 MW |
| 31 Oct, 00:00 | 568 MW | 891 MW |
| 31 Oct, 01:00 | 602 MW | 832 MW |
| 31 Oct, 02:00 | 617 MW | 704 MW |
| 31 Oct, 03:00 | 566 MW | 700 MW |
| 31 Oct, 04:00 | 627 MW | 713 MW |
| 31 Oct, 05:00 | 582 MW | 725 MW |
| 31 Oct, 06:00 | 546 MW | 726 MW |
| 31 Oct, 07:00 | 482 MW | 724 MW |
| 31 Oct, 08:00 | 788 MW | 933 MW |
| 31 Oct, 09:00 | 861 MW | 873 MW |
| 31 Oct, 10:00 | 789 MW | 894 MW |
| 31 Oct, 11:00 | 836 MW | 864 MW |
| 31 Oct, 12:00 | 826 MW | 891 MW |
| 31 Oct, 13:00 | 813 MW | 908 MW |
| 31 Oct, 14:00 | 823 MW | 962 MW |
| 31 Oct, 15:00 | 803 MW | 975 MW |
| 31 Oct, 16:00 | 486 MW | 944 MW |
| 31 Oct, 17:00 | 558 MW | 1,073 MW |
| 31 Oct, 18:00 | 577 MW | 1,073 MW |
| 31 Oct, 19:00 | 693 MW | 1,078 MW |
| 31 Oct, 20:00 | 756 MW | 959 MW |
| 31 Oct, 21:00 | 740 MW | 938 MW |
| 31 Oct, 22:00 | 638 MW | 940 MW |
| 31 Oct, 23:00 | 568 MW | 762 MW |
| 1 Nov, 00:00 | 525 MW | 646 MW |
| 1 Nov, 01:00 | 700 MW | 625 MW |
| 1 Nov, 02:00 | 518 MW | 631 MW |
| 1 Nov, 03:00 | 502 MW | 683 MW |
| 1 Nov, 04:00 | 497 MW | 672 MW |
| 1 Nov, 05:00 | 560 MW | 660 MW |
| 1 Nov, 06:00 | 551 MW | 668 MW |
| 1 Nov, 07:00 | 431 MW | 671 MW |
| 1 Nov, 08:00 | 424 MW | 881 MW |
| 1 Nov, 09:00 | 690 MW | 805 MW |
| 1 Nov, 10:00 | 731 MW | 812 MW |
| 1 Nov, 11:00 | 759 MW | 830 MW |
| 1 Nov, 12:00 | 822 MW | 875 MW |
| 1 Nov, 13:00 | 848 MW | 886 MW |
| 1 Nov, 14:00 | 941 MW | 878 MW |
| 1 Nov, 15:00 | 865 MW | 891 MW |
| 1 Nov, 16:00 | 741 MW | 778 MW |
| 1 Nov, 17:00 | 635 MW | 964 MW |
| 1 Nov, 18:00 | 580 MW | 928 MW |
| 1 Nov, 19:00 | 777 MW | 970 MW |
| 1 Nov, 20:00 | 791 MW | 850 MW |
| 1 Nov, 21:00 | 774 MW | 804 MW |
| 1 Nov, 22:00 | 696 MW | 717 MW |
| 1 Nov, 23:00 | 675 MW | 591 MW |
| 2 Nov, 00:00 | 512 MW | 535 MW |
| 2 Nov, 01:00 | 508 MW | 520 MW |
| 2 Nov, 02:00 | 506 MW | 497 MW |
| 2 Nov, 03:00 | 500 MW | 507 MW |
| 2 Nov, 04:00 | 538 MW | 556 MW |
| 2 Nov, 05:00 | 610 MW | 650 MW |
| 2 Nov, 06:00 | 586 MW | 768 MW |
| 2 Nov, 07:00 | 463 MW | 750 MW |
| 2 Nov, 08:00 | 415 MW | 811 MW |
| 2 Nov, 09:00 | 667 MW | 794 MW |
| 2 Nov, 10:00 | 634 MW | 793 MW |
| 2 Nov, 11:00 | 649 MW | 787 MW |
| 2 Nov, 12:00 | 642 MW | 801 MW |
| 2 Nov, 13:00 | 683 MW | 862 MW |
| 2 Nov, 14:00 | 670 MW | 931 MW |
| 2 Nov, 15:00 | 664 MW | 1,465 MW |
| 2 Nov, 16:00 | 588 MW | 818 MW |
| 2 Nov, 17:00 | 695 MW | 913 MW |
| 2 Nov, 18:00 | 779 MW | 966 MW |
| 2 Nov, 19:00 | 835 MW | 977 MW |
| 2 Nov, 20:00 | 856 MW | 827 MW |
| 2 Nov, 21:00 | 758 MW | 804 MW |
| 2 Nov, 22:00 | 712 MW | 748 MW |
| 2 Nov, 23:00 | 653 MW | 627 MW |
| 3 Nov, 00:00 | 496 MW | 524 MW |
| 3 Nov, 01:00 | 534 MW | 551 MW |
| 3 Nov, 02:00 | 411 MW | 497 MW |
| 3 Nov, 03:00 | 416 MW | 477 MW |
| 3 Nov, 04:00 | 464 MW | 499 MW |
| 3 Nov, 05:00 | 516 MW | 530 MW |
| 3 Nov, 06:00 | 609 MW | 707 MW |
| 3 Nov, 07:00 | 511 MW | 786 MW |
| 3 Nov, 08:00 | 419 MW | 694 MW |
| 3 Nov, 09:00 | 603 MW | 681 MW |
| 3 Nov, 10:00 | 604 MW | 687 MW |
| 3 Nov, 11:00 | 584 MW | 745 MW |
| 3 Nov, 12:00 | 590 MW | 724 MW |
| 3 Nov, 13:00 | 558 MW | 718 MW |
| 3 Nov, 14:00 | 603 MW | 758 MW |
| 3 Nov, 15:00 | 637 MW | 827 MW |
| 3 Nov, 16:00 | 612 MW | 701 MW |
| 3 Nov, 17:00 | 687 MW | 750 MW |
| 3 Nov, 18:00 | 643 MW | 706 MW |
| 3 Nov, 19:00 | 812 MW | 762 MW |
| 3 Nov, 20:00 | 644 MW | 821 MW |
| 3 Nov, 21:00 | 747 MW | 782 MW |
| 3 Nov, 22:00 | 609 MW | 612 MW |
| 3 Nov, 23:00 | 574 MW | 657 MW |
| 4 Nov, 00:00 | 640 MW | 571 MW |
| 4 Nov, 01:00 | 414 MW | 565 MW |
| 4 Nov, 02:00 | 458 MW | 560 MW |
| 4 Nov, 03:00 | 490 MW | 561 MW |
| 4 Nov, 04:00 | 529 MW | 558 MW |
| 4 Nov, 05:00 | 565 MW | 638 MW |
| 4 Nov, 06:00 | 816 MW | 639 MW |
| 4 Nov, 07:00 | 694 MW | 530 MW |
| 4 Nov, 08:00 | 522 MW | 723 MW |
| 4 Nov, 09:00 | 772 MW | 694 MW |
| 4 Nov, 10:00 | 788 MW | 741 MW |
| 4 Nov, 11:00 | 751 MW | 784 MW |
| 4 Nov, 12:00 | 671 MW | 808 MW |
| 4 Nov, 13:00 | 703 MW | 879 MW |
| 4 Nov, 14:00 | 679 MW | 887 MW |
| 4 Nov, 15:00 | 687 MW | 896 MW |
| 4 Nov, 16:00 | 617 MW | 730 MW |
| 4 Nov, 17:00 | 803 MW | 677 MW |
| 4 Nov, 18:00 | 795 MW | 942 MW |
| 4 Nov, 19:00 | 906 MW | 865 MW |
| 4 Nov, 20:00 | 758 MW | 888 MW |
| 4 Nov, 21:00 | 788 MW | 812 MW |
| 4 Nov, 22:00 | 666 MW | 694 MW |
| 4 Nov, 23:00 | 637 MW | 629 MW |
| 5 Nov, 00:00 | 474 MW | 584 MW |
| 5 Nov, 01:00 | 476 MW | 557 MW |
| 5 Nov, 02:00 | 453 MW | 582 MW |
| 5 Nov, 03:00 | 453 MW | 611 MW |
| 5 Nov, 04:00 | 466 MW | 631 MW |
| 5 Nov, 05:00 | 483 MW | 684 MW |
| 5 Nov, 06:00 | 671 MW | 698 MW |
Assumptions
- Only hours with both a forecast and a positive demand reading count (719 of 720 hours in the window). Missing and zero values, and readings under 30% or over 3 times the grid's own median for the window, are treated as reporting faults and left out.
- Error is (forecast minus reported demand) divided by reported demand; average error uses absolute values so high and low misses do not cancel. Bias keeps the sign and does cancel.
- Reported demand is preliminary and may be revised. A 30 day window is a short sample and one heat wave or holiday can move these figures.
- US figures are for the EIA balancing authority or region named on this page. US and European grids are ranked separately.
Related
Cite this page
APA 7
World Power Monitor. (2026). WALC Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/walc/
Plain text
World Power Monitor. WALC Demand Forecast Accuracy: Error, Bias and Worst Miss. Data as of 2026-11-05. Data from U.S. Energy Information Administration. https://worldpowermonitor.com/forecast-accuracy/walc/
BibTeX
@misc{wpm_forecast_accuracy_walc_2026,
title = {{WALC Demand Forecast Accuracy: Error, Bias and Worst Miss}},
author = {{World Power Monitor}},
year = {2026},
note = {Data as of 2026-11-05. Data from U.S. Energy Information Administration.},
url = {https://worldpowermonitor.com/forecast-accuracy/walc/}
} Permalink: https://worldpowermonitor.com/forecast-accuracy/walc/
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