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Data as of 2026-10-28
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Built 2026-10-28 (28 October 2026)

SRP Demand Forecast Accuracy: Error, Bias and Worst Miss, 28 September to 28 October 2026

The day-ahead demand forecast for SRP was off by 26.8% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 24% of hours landed within 5% of the reading. Its bias was +25.9%: it ran high on average, an over forecast. The largest miss was 2,700 MW (129.6%) too high at 28 Sept 2026, 17:00 MST (UTC-07:00). Dates and times are local (America/Phoenix).

Key Facts

  • The day-ahead demand forecast for SRP was off by 26.8% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 24% of hours landed within 5% of the reading. Its bias was +25.9%: it ran high on average, an over forecast. The largest miss was 2,700 MW (129.6%) too high at 28 Sept 2026, 17:00 MST (UTC-07:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, SRP came 51 (1 is the smallest error).
  • On average the forecast differed from reported demand by 736 MW, against average demand of 3,502 MW.
  • The forecast was above reported demand in 85% of compared hours.

Forecast Error at a Glance

719 hours from 28 September to 28 October 2026
Average error26.8%
Bias+25.9%
Hours within 5%24%
Worst miss2,700 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+698 MW per hour on average): the forecast ran high on average, an over forecast. The worst miss was 2,700 MW (129.6%) too high at 28 Sept 2026, 17:00 MST (UTC-07:00): forecast 4,784 MW, reported 2,084 MW.

Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) Data as of 2026-10-28. 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 28 Oct 2026, 04:00 MST (UTC-07:00)
SRP day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for SRP over the last 7 days of the window, to 28 Oct 2026, 04:00 MST (UTC-07:00). Gaps are hours with a missing, zero or implausible report. 0 1,500 3,000 4,500 6,000 21 Oct, 05:0022 Oct, 05:0023 Oct, 05:0024 Oct, 05:0025 Oct, 05:0026 Oct, 05:0027 Oct, 05:00
Hourly reported demand and the day-ahead forecast for SRP over the last 7 days of the window, to 28 Oct 2026, 04:00 MST (UTC-07:00). Gaps are hours with a missing, zero or implausible report.
Data to 2026-10-28
Show the data table (168 rows)
Local hourReported demandDay-ahead forecast
21 Oct, 05:003,709 MW3,794 MW
21 Oct, 06:003,679 MW3,879 MW
21 Oct, 07:003,755 MW3,908 MW
21 Oct, 08:003,923 MW4,013 MW
21 Oct, 09:004,075 MW4,175 MW
21 Oct, 10:004,261 MW4,378 MW
21 Oct, 11:004,499 MW4,571 MW
21 Oct, 12:004,531 MW4,836 MW
21 Oct, 13:004,589 MW5,034 MW
21 Oct, 14:004,675 MW5,142 MW
21 Oct, 15:004,341 MW5,160 MW
21 Oct, 16:004,174 MW5,148 MW
21 Oct, 17:004,288 MW5,068 MW
21 Oct, 18:004,108 MW4,976 MW
21 Oct, 19:003,950 MW4,800 MW
21 Oct, 20:003,958 MW4,681 MW
21 Oct, 21:003,893 MW4,474 MW
21 Oct, 22:003,541 MW4,196 MW
21 Oct, 23:003,205 MW3,956 MW
22 Oct, 00:002,869 MW3,895 MW
22 Oct, 01:003,039 MW3,735 MW
22 Oct, 02:003,262 MW3,635 MW
22 Oct, 03:003,270 MW3,593 MW
22 Oct, 04:003,388 MW3,629 MW
22 Oct, 05:003,649 MW3,759 MW
22 Oct, 06:003,917 MW3,874 MW
22 Oct, 07:004,005 MW3,912 MW
22 Oct, 08:004,105 MW4,007 MW
22 Oct, 09:003,880 MW4,139 MW
22 Oct, 10:003,618 MW4,293 MW
22 Oct, 11:003,702 MW4,434 MW
22 Oct, 12:003,829 MW4,575 MW
22 Oct, 13:003,797 MW4,673 MW
22 Oct, 14:003,821 MW4,665 MW
22 Oct, 15:003,723 MW4,621 MW
22 Oct, 16:003,383 MW4,611 MW
22 Oct, 17:003,269 MW4,483 MW
22 Oct, 18:003,271 MW4,430 MW
22 Oct, 19:003,279 MW4,329 MW
22 Oct, 20:003,318 MW4,265 MW
22 Oct, 21:003,140 MW4,112 MW
22 Oct, 22:003,118 MW3,892 MW
22 Oct, 23:003,389 MW3,702 MW
23 Oct, 00:003,523 MW3,604 MW
23 Oct, 01:003,302 MW3,393 MW
23 Oct, 02:003,117 MW3,240 MW
23 Oct, 03:003,231 MW3,168 MW
23 Oct, 04:003,208 MW3,223 MW
23 Oct, 05:003,304 MW3,335 MW
23 Oct, 06:003,425 MW3,447 MW
23 Oct, 07:003,380 MW3,464 MW
23 Oct, 08:003,204 MW3,466 MW
23 Oct, 09:003,052 MW3,505 MW
23 Oct, 10:003,070 MW3,600 MW
23 Oct, 11:003,116 MW3,731 MW
23 Oct, 12:002,924 MW3,885 MW
23 Oct, 13:002,811 MW4,036 MW
23 Oct, 14:002,979 MW4,169 MW
23 Oct, 15:002,823 MW4,270 MW
23 Oct, 16:003,116 MW4,240 MW
23 Oct, 17:003,156 MW4,047 MW
23 Oct, 18:003,121 MW3,954 MW
23 Oct, 19:002,371 MW3,891 MW
23 Oct, 20:003,507 MW3,804 MW
23 Oct, 21:003,342 MW3,691 MW
23 Oct, 22:002,996 MW3,531 MW
23 Oct, 23:002,834 MW3,372 MW
24 Oct, 00:002,863 MW3,369 MW
24 Oct, 01:002,201 MW3,267 MW
24 Oct, 02:001,868 MW3,155 MW
24 Oct, 03:001,991 MW3,078 MW
24 Oct, 04:002,089 MW3,054 MW
24 Oct, 05:002,118 MW3,086 MW
24 Oct, 06:002,308 MW3,173 MW
24 Oct, 07:002,317 MW3,240 MW
24 Oct, 08:001,800 MW3,285 MW
24 Oct, 09:001,668 MW3,329 MW
24 Oct, 10:001,499 MW3,368 MW
24 Oct, 11:001,495 MW3,439 MW
24 Oct, 12:001,642 MW3,522 MW
24 Oct, 13:001,724 MW3,625 MW
24 Oct, 14:001,779 MW3,686 MW
24 Oct, 15:001,768 MW3,785 MW
24 Oct, 16:001,934 MW3,801 MW
24 Oct, 17:002,023 MW3,707 MW
24 Oct, 18:002,024 MW3,637 MW
24 Oct, 19:002,309 MW3,586 MW
24 Oct, 20:002,777 MW3,562 MW
24 Oct, 21:002,817 MW3,478 MW
24 Oct, 22:003,068 MW3,352 MW
24 Oct, 23:003,255 MW3,252 MW
25 Oct, 00:002,974 MW3,278 MW
25 Oct, 01:002,656 MW3,211 MW
25 Oct, 02:002,694 MW3,086 MW
25 Oct, 03:002,801 MW2,996 MW
25 Oct, 04:002,804 MW2,977 MW
25 Oct, 05:002,733 MW3,007 MW
25 Oct, 06:002,798 MW3,090 MW
25 Oct, 07:002,764 MW3,151 MW
25 Oct, 08:002,822 MW3,208 MW
25 Oct, 09:002,685 MW3,289 MW
25 Oct, 10:003,073 MW3,376 MW
25 Oct, 11:003,093 MW3,510 MW
25 Oct, 12:003,135 MW3,672 MW
25 Oct, 13:003,423 MW3,824 MW
25 Oct, 14:003,693 MW3,959 MW
25 Oct, 15:003,591 MW4,099 MW
25 Oct, 16:003,541 MW4,131 MW
25 Oct, 17:003,691 MW4,063 MW
25 Oct, 18:003,585 MW3,970 MW
25 Oct, 19:003,591 MW3,897 MW
25 Oct, 20:003,612 MW3,816 MW
25 Oct, 21:003,278 MW3,668 MW
25 Oct, 22:003,197 MW3,468 MW
25 Oct, 23:003,131 MW3,295 MW
26 Oct, 00:003,092 MW3,252 MW
26 Oct, 01:003,072 MW3,188 MW
26 Oct, 02:003,076 MW3,093 MW
26 Oct, 03:003,101 MW3,076 MW
26 Oct, 04:003,107 MW3,156 MW
26 Oct, 05:003,161 MW3,321 MW
26 Oct, 06:003,205 MW3,472 MW
26 Oct, 07:003,289 MW3,462 MW
26 Oct, 08:003,273 MW3,414 MW
26 Oct, 09:003,302 MW3,426 MW
26 Oct, 10:003,344 MW3,506 MW
26 Oct, 11:003,437 MW3,649 MW
26 Oct, 12:003,411 MW3,842 MW
26 Oct, 13:003,263 MW4,042 MW
26 Oct, 14:003,386 MW4,207 MW
26 Oct, 15:003,609 MW4,338 MW
26 Oct, 16:003,901 MW4,408 MW
26 Oct, 17:004,276 MW4,327 MW
26 Oct, 18:004,461 MW4,239 MW
26 Oct, 19:004,337 MW4,127 MW
26 Oct, 20:004,254 MW4,009 MW
26 Oct, 21:004,041 MW3,825 MW
26 Oct, 22:003,734 MW3,583 MW
26 Oct, 23:003,441 MW3,382 MW
27 Oct, 00:003,245 MW3,372 MW
27 Oct, 01:003,094 MW3,211 MW
27 Oct, 02:002,840 MW3,130 MW
27 Oct, 03:002,724 MW3,098 MW
27 Oct, 04:002,637 MW3,175 MW
27 Oct, 05:002,671 MW3,330 MW
27 Oct, 06:002,725 MW3,472 MW
27 Oct, 07:002,578 MW3,445 MW
27 Oct, 08:002,330 MW3,401 MW
27 Oct, 09:001,908 MW3,427 MW
27 Oct, 10:001,685 MW3,509 MW
27 Oct, 11:001,708 MW3,677 MW
27 Oct, 12:001,814 MW3,892 MW
27 Oct, 13:002,014 MW4,109 MW
27 Oct, 14:002,263 MW4,290 MW
27 Oct, 15:002,538 MW4,439 MW
27 Oct, 16:003,223 MW4,511 MW
27 Oct, 17:003,835 MW4,425 MW
27 Oct, 18:003,938 MW4,323 MW
27 Oct, 19:003,795 MW4,205 MW
27 Oct, 20:003,487 MW4,086 MW
27 Oct, 21:003,028 MW3,882 MW
27 Oct, 22:002,559 MW3,631 MW
27 Oct, 23:002,306 MW3,422 MW
28 Oct, 00:002,257 MW3,329 MW
28 Oct, 01:002,177 MW3,196 MW
28 Oct, 02:002,006 MW3,096 MW
28 Oct, 03:001,671 MW3,065 MW
28 Oct, 04:001,766 MW3,151 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). SRP Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/srp/

Plain text

World Power Monitor. SRP Demand Forecast Accuracy: Error, Bias and Worst Miss. Data as of 2026-10-28. Data from U.S. Energy Information Administration. https://worldpowermonitor.com/forecast-accuracy/srp/

BibTeX 
@misc{wpm_forecast_accuracy_srp_2026,
  title = {{SRP Demand Forecast Accuracy: Error, Bias and Worst Miss}},
  author = {{World Power Monitor}},
  year = {2026},
  note = {Data as of 2026-10-28. Data from U.S. Energy Information Administration.},
  url = {https://worldpowermonitor.com/forecast-accuracy/srp/}
}

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