WALC Demand Forecast Accuracy: Error, Bias and Worst Miss, 13 October to 12 November 2026

The day-ahead demand forecast for WALC was off by 20.0% on average (mean absolute percentage error) over 719 hours from 13 October to 12 November 2026, and 16% of hours landed within 5% of the reading. Its bias was +13.2%: 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 20.0% on average (mean absolute percentage error) over 719 hours from 13 October to 12 November 2026, and 16% of hours landed within 5% of the reading. Its bias was +13.2%: 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 137 MW, against average demand of 749 MW.
The forecast was above reported demand in 70% of compared hours.

Forecast Error at a Glance

719 hours from 13 October to 12 November 2026

Average error20.0%

Bias+13.2%

Hours within 5%16%

Worst miss801 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+80 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 2026-11-12. 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 12 Nov 2026, 05:00 MST (UTC-07:00)

Hourly reported demand and the day-ahead forecast for WALC over the last 7 days of the window, to 12 Nov 2026, 05:00 MST (UTC-07:00). Gaps are hours with a missing, zero or implausible report.

Data to 2026-11-12

Show the data table (168 rows)

Local hour	Reported demand	Day-ahead forecast
5 Nov, 06:00	672 MW	698 MW
5 Nov, 07:00	667 MW	576 MW
5 Nov, 08:00	479 MW	840 MW
5 Nov, 09:00	571 MW	819 MW
5 Nov, 10:00	662 MW	859 MW
5 Nov, 11:00	659 MW	872 MW
5 Nov, 12:00	635 MW	820 MW
5 Nov, 13:00	563 MW	841 MW
5 Nov, 14:00	665 MW	826 MW
5 Nov, 15:00	735 MW	855 MW
5 Nov, 16:00	643 MW	806 MW
5 Nov, 17:00	754 MW	795 MW
5 Nov, 18:00	798 MW	873 MW
5 Nov, 19:00	825 MW	868 MW
5 Nov, 20:00	725 MW	920 MW
5 Nov, 21:00	671 MW	935 MW
5 Nov, 22:00	613 MW	915 MW
5 Nov, 23:00	468 MW	764 MW
6 Nov, 00:00	462 MW	676 MW
6 Nov, 01:00	463 MW	634 MW
6 Nov, 02:00	447 MW	643 MW
6 Nov, 03:00	441 MW	628 MW
6 Nov, 04:00	466 MW	650 MW
6 Nov, 05:00	647 MW	646 MW
6 Nov, 06:00	758 MW	896 MW
6 Nov, 07:00	516 MW	704 MW
6 Nov, 08:00	496 MW	868 MW
6 Nov, 09:00	702 MW	924 MW
6 Nov, 10:00	629 MW	922 MW
6 Nov, 11:00	622 MW	993 MW
6 Nov, 12:00	598 MW	988 MW
6 Nov, 13:00	587 MW	1,011 MW
6 Nov, 14:00	592 MW	987 MW
6 Nov, 15:00	615 MW	988 MW
6 Nov, 16:00	553 MW	796 MW
6 Nov, 17:00	709 MW	775 MW
6 Nov, 18:00	740 MW	887 MW
6 Nov, 19:00	679 MW	946 MW
6 Nov, 20:00	667 MW	891 MW
6 Nov, 21:00	637 MW	814 MW
6 Nov, 22:00	515 MW	674 MW
6 Nov, 23:00	409 MW	617 MW
7 Nov, 00:00	592 MW	568 MW
7 Nov, 01:00	474 MW	602 MW
7 Nov, 02:00	468 MW	617 MW
7 Nov, 03:00	457 MW	566 MW
7 Nov, 04:00	468 MW	627 MW
7 Nov, 05:00	450 MW	582 MW
7 Nov, 06:00	539 MW	546 MW
7 Nov, 07:00	578 MW	482 MW
7 Nov, 08:00	347 MW	788 MW
7 Nov, 09:00	556 MW	861 MW
7 Nov, 10:00	528 MW	789 MW
7 Nov, 11:00	530 MW	836 MW
7 Nov, 12:00	558 MW	826 MW
7 Nov, 13:00	566 MW	813 MW
7 Nov, 14:00	599 MW	823 MW
7 Nov, 15:00	649 MW	803 MW
7 Nov, 16:00	647 MW	486 MW
7 Nov, 17:00	642 MW	558 MW
7 Nov, 18:00	647 MW	577 MW
7 Nov, 19:00	822 MW	693 MW
7 Nov, 20:00	720 MW	756 MW
7 Nov, 21:00	701 MW	740 MW
7 Nov, 22:00	665 MW	638 MW
7 Nov, 23:00	495 MW	569 MW
8 Nov, 00:00	486 MW	525 MW
8 Nov, 01:00	470 MW	700 MW
8 Nov, 02:00	424 MW	518 MW
8 Nov, 03:00	438 MW	502 MW
8 Nov, 04:00	456 MW	497 MW
8 Nov, 05:00	467 MW	560 MW
8 Nov, 06:00	497 MW	551 MW
8 Nov, 07:00	439 MW	431 MW
8 Nov, 08:00	301 MW	424 MW
8 Nov, 09:00	547 MW	690 MW
8 Nov, 10:00	575 MW	731 MW
8 Nov, 11:00	590 MW	759 MW
8 Nov, 12:00	561 MW	822 MW
8 Nov, 13:00	579 MW	848 MW
8 Nov, 14:00	553 MW	941 MW
8 Nov, 15:00	603 MW	865 MW
8 Nov, 16:00	590 MW	741 MW
8 Nov, 17:00	579 MW	635 MW
8 Nov, 18:00	634 MW	580 MW
8 Nov, 19:00	670 MW	777 MW
8 Nov, 20:00	740 MW	791 MW
8 Nov, 21:00	665 MW	774 MW
8 Nov, 22:00	655 MW	696 MW
8 Nov, 23:00	404 MW	673 MW
9 Nov, 00:00	387 MW	512 MW
9 Nov, 01:00	403 MW	508 MW
9 Nov, 02:00	425 MW	506 MW
9 Nov, 03:00	454 MW	500 MW
9 Nov, 04:00	539 MW	538 MW
9 Nov, 05:00	532 MW	610 MW
9 Nov, 06:00	556 MW	586 MW
9 Nov, 07:00	617 MW	463 MW
9 Nov, 08:00	465 MW	415 MW
9 Nov, 09:00	677 MW	667 MW
9 Nov, 10:00	661 MW	634 MW
9 Nov, 11:00	607 MW	649 MW
9 Nov, 12:00	583 MW	642 MW
9 Nov, 13:00	583 MW	683 MW
9 Nov, 14:00	553 MW	670 MW
9 Nov, 15:00	612 MW	664 MW
9 Nov, 16:00	604 MW	588 MW
9 Nov, 17:00	724 MW	695 MW
9 Nov, 18:00	717 MW	779 MW
9 Nov, 19:00	733 MW	835 MW
9 Nov, 20:00	751 MW	856 MW
9 Nov, 21:00	626 MW	758 MW
9 Nov, 22:00	608 MW	712 MW
9 Nov, 23:00	500 MW	653 MW
10 Nov, 00:00	563 MW	496 MW
10 Nov, 01:00	554 MW	534 MW
10 Nov, 02:00	567 MW	411 MW
10 Nov, 03:00	553 MW	416 MW
10 Nov, 04:00	552 MW	464 MW
10 Nov, 05:00	582 MW	516 MW
10 Nov, 06:00	572 MW	609 MW
10 Nov, 07:00	485 MW	511 MW
10 Nov, 08:00	592 MW	419 MW
10 Nov, 09:00	591 MW	603 MW
10 Nov, 10:00	546 MW	604 MW
10 Nov, 11:00	563 MW	584 MW
10 Nov, 12:00	574 MW	590 MW
10 Nov, 13:00	596 MW	558 MW
10 Nov, 14:00	597 MW	603 MW
10 Nov, 15:00	686 MW	637 MW
10 Nov, 16:00	646 MW	612 MW
10 Nov, 17:00	761 MW	687 MW
10 Nov, 18:00	708 MW	643 MW
10 Nov, 19:00	666 MW	812 MW
10 Nov, 20:00	778 MW	644 MW
10 Nov, 21:00	695 MW	747 MW
10 Nov, 22:00	797 MW	609 MW
10 Nov, 23:00	616 MW	575 MW
11 Nov, 00:00	640 MW	640 MW
11 Nov, 01:00	605 MW	414 MW
11 Nov, 02:00	581 MW	458 MW
11 Nov, 03:00	548 MW	490 MW
11 Nov, 04:00	519 MW	529 MW
11 Nov, 05:00	578 MW	565 MW
11 Nov, 06:00	561 MW	816 MW
11 Nov, 07:00	530 MW	694 MW
11 Nov, 08:00	633 MW	522 MW
11 Nov, 09:00	622 MW	772 MW
11 Nov, 10:00	659 MW	788 MW
11 Nov, 11:00	655 MW	751 MW
11 Nov, 12:00	619 MW	671 MW
11 Nov, 13:00	574 MW	703 MW
11 Nov, 14:00	576 MW	679 MW
11 Nov, 15:00	628 MW	687 MW
11 Nov, 16:00	656 MW	617 MW
11 Nov, 17:00	804 MW	803 MW
11 Nov, 18:00	814 MW	795 MW
11 Nov, 19:00	791 MW	906 MW
11 Nov, 20:00	785 MW	758 MW
11 Nov, 21:00	681 MW	788 MW
11 Nov, 22:00	673 MW	666 MW
11 Nov, 23:00	590 MW	633 MW
12 Nov, 00:00	592 MW	474 MW
12 Nov, 01:00	615 MW	476 MW
12 Nov, 02:00	588 MW	453 MW
12 Nov, 03:00	561 MW	453 MW
12 Nov, 04:00	568 MW	466 MW
12 Nov, 05:00	582 MW	483 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.

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 2026-11-12. 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 2026-11-12. 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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WALC Demand Forecast Accuracy: Error, Bias and Worst Miss, 13 October to 12 November 2026

Key Facts

Forecast Error at a Glance

Forecast and Reported Demand, Last 7 Days

Assumptions

Related