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

The day-ahead demand forecast for ISO-NE was off by 3.6% on average (mean absolute percentage error) over 719 hours from 13 October to 12 November 2026, and 71% of hours landed within 5% of the reading. Its bias was -3.1%: it ran low on average, an under forecast. The largest miss was 1,662 MW (17.6%) too low at 23 Oct 2026, 11:00 EDT (UTC-04:00). Dates and times are local (America/New_York).

Key Facts

The day-ahead demand forecast for ISO-NE was off by 3.6% on average (mean absolute percentage error) over 719 hours from 13 October to 12 November 2026, and 71% of hours landed within 5% of the reading. Its bias was -3.1%: it ran low on average, an under forecast. The largest miss was 1,662 MW (17.6%) too low at 23 Oct 2026, 11:00 EDT (UTC-04:00).
Across 53 US grids ranked by average error over their own latest 30 day windows, ISO-NE came 25 (1 is the smallest error).
On average the forecast differed from reported demand by 380 MW, against average demand of 11,615 MW.
The forecast was above reported demand in 22% of compared hours.

Forecast Error at a Glance

719 hours from 13 October to 12 November 2026

Average error3.6%

Bias-3.1%

Hours within 5%71%

Worst miss1,662 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-321 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 1,662 MW (17.6%) too low at 23 Oct 2026, 11:00 EDT (UTC-04:00): forecast 7,760 MW, reported 9,422 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, 07:00 EST (UTC-05:00)

Hourly reported demand and the day-ahead forecast for ISO-NE over the last 7 days of the window, to 12 Nov 2026, 07:00 EST (UTC-05:00). 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, 08:00	12,098 MW	12,360 MW
5 Nov, 09:00	11,965 MW	11,770 MW
5 Nov, 10:00	12,267 MW	12,260 MW
5 Nov, 11:00	12,578 MW	12,360 MW
5 Nov, 12:00	12,917 MW	12,620 MW
5 Nov, 13:00	13,253 MW	12,860 MW
5 Nov, 14:00	13,380 MW	13,320 MW
5 Nov, 15:00	13,632 MW	13,780 MW
5 Nov, 16:00	14,230 MW	14,400 MW
5 Nov, 17:00	14,802 MW	14,900 MW
5 Nov, 18:00	14,593 MW	14,530 MW
5 Nov, 19:00	14,161 MW	14,080 MW
5 Nov, 20:00	13,595 MW	13,560 MW
5 Nov, 21:00	12,891 MW	12,770 MW
5 Nov, 22:00	11,981 MW	11,840 MW
5 Nov, 23:00	11,119 MW	11,100 MW
6 Nov, 00:00	10,935 MW	10,630 MW
6 Nov, 01:00	10,935 MW	10,170 MW
6 Nov, 02:00	10,766 MW	9,990 MW
6 Nov, 03:00	10,706 MW	9,880 MW
6 Nov, 04:00	10,740 MW	10,120 MW
6 Nov, 05:00	11,254 MW	10,860 MW
6 Nov, 06:00	12,369 MW	12,130 MW
6 Nov, 07:00	13,058 MW	12,880 MW
6 Nov, 08:00	13,467 MW	13,090 MW
6 Nov, 09:00	13,852 MW	13,340 MW
6 Nov, 10:00	13,718 MW	13,490 MW
6 Nov, 11:00	13,646 MW	13,460 MW
6 Nov, 12:00	13,449 MW	13,400 MW
6 Nov, 13:00	13,483 MW	13,520 MW
6 Nov, 14:00	13,642 MW	13,640 MW
6 Nov, 15:00	13,864 MW	13,740 MW
6 Nov, 16:00	14,309 MW	14,090 MW
6 Nov, 17:00	14,548 MW	14,750 MW
6 Nov, 18:00	14,080 MW	14,190 MW
6 Nov, 19:00	13,613 MW	13,650 MW
6 Nov, 20:00	13,060 MW	12,980 MW
6 Nov, 21:00	12,645 MW	12,270 MW
6 Nov, 22:00	11,903 MW	11,510 MW
6 Nov, 23:00	11,406 MW	10,810 MW
7 Nov, 00:00	10,867 MW	10,420 MW
7 Nov, 01:00	10,421 MW	9,910 MW
7 Nov, 02:00	10,429 MW	9,680 MW
7 Nov, 03:00	10,478 MW	9,510 MW
7 Nov, 04:00	10,326 MW	9,590 MW
7 Nov, 05:00	10,528 MW	9,880 MW
7 Nov, 06:00	10,703 MW	10,420 MW
7 Nov, 07:00	11,165 MW	10,930 MW
7 Nov, 08:00	11,382 MW	11,280 MW
7 Nov, 09:00	11,649 MW	11,550 MW
7 Nov, 10:00	11,724 MW	11,600 MW
7 Nov, 11:00	11,700 MW	11,530 MW
7 Nov, 12:00	11,743 MW	11,540 MW
7 Nov, 13:00	11,938 MW	11,610 MW
7 Nov, 14:00	12,128 MW	11,920 MW
7 Nov, 15:00	12,483 MW	12,480 MW
7 Nov, 16:00	13,133 MW	13,120 MW
7 Nov, 17:00	13,519 MW	13,600 MW
7 Nov, 18:00	13,225 MW	13,340 MW
7 Nov, 19:00	12,752 MW	12,900 MW
7 Nov, 20:00	12,261 MW	12,360 MW
7 Nov, 21:00	11,726 MW	11,800 MW
7 Nov, 22:00	11,109 MW	11,120 MW
7 Nov, 23:00	10,603 MW	10,500 MW
8 Nov, 00:00	10,214 MW	9,920 MW
8 Nov, 01:00	10,155 MW	9,540 MW
8 Nov, 02:00	10,138 MW	9,290 MW
8 Nov, 03:00	10,058 MW	9,180 MW
8 Nov, 04:00	10,082 MW	9,240 MW
8 Nov, 05:00	10,340 MW	9,520 MW
8 Nov, 06:00	10,579 MW	9,980 MW
8 Nov, 07:00	10,658 MW	10,180 MW
8 Nov, 08:00	11,016 MW	10,220 MW
8 Nov, 09:00	10,791 MW	9,960 MW
8 Nov, 10:00	10,661 MW	9,810 MW
8 Nov, 11:00	10,938 MW	9,800 MW
8 Nov, 12:00	11,348 MW	10,330 MW
8 Nov, 13:00	10,872 MW	10,300 MW
8 Nov, 14:00	10,965 MW	10,790 MW
8 Nov, 15:00	11,970 MW	11,870 MW
8 Nov, 16:00	13,321 MW	13,200 MW
8 Nov, 17:00	14,068 MW	14,200 MW
8 Nov, 18:00	13,855 MW	13,900 MW
8 Nov, 19:00	13,480 MW	13,470 MW
8 Nov, 20:00	12,947 MW	12,900 MW
8 Nov, 21:00	12,183 MW	12,160 MW
8 Nov, 22:00	11,317 MW	11,270 MW
8 Nov, 23:00	10,809 MW	10,550 MW
9 Nov, 00:00	10,375 MW	9,940 MW
9 Nov, 01:00	10,074 MW	9,620 MW
9 Nov, 02:00	9,851 MW	9,460 MW
9 Nov, 03:00	10,089 MW	9,510 MW
9 Nov, 04:00	10,232 MW	9,880 MW
9 Nov, 05:00	11,070 MW	10,850 MW
9 Nov, 06:00	12,281 MW	12,340 MW
9 Nov, 07:00	12,629 MW	12,900 MW
9 Nov, 08:00	12,591 MW	12,280 MW
9 Nov, 09:00	12,459 MW	12,450 MW
9 Nov, 10:00	12,137 MW	12,360 MW
9 Nov, 11:00	11,785 MW	12,270 MW
9 Nov, 12:00	11,787 MW	11,550 MW
9 Nov, 13:00	12,141 MW	11,770 MW
9 Nov, 14:00	12,457 MW	12,310 MW
9 Nov, 15:00	13,108 MW	13,110 MW
9 Nov, 16:00	14,135 MW	14,180 MW
9 Nov, 17:00	14,840 MW	14,900 MW
9 Nov, 18:00	14,731 MW	14,700 MW
9 Nov, 19:00	14,263 MW	14,260 MW
9 Nov, 20:00	13,714 MW	13,610 MW
9 Nov, 21:00	12,918 MW	12,790 MW
9 Nov, 22:00	11,968 MW	11,830 MW
9 Nov, 23:00	11,139 MW	10,980 MW
10 Nov, 00:00	10,889 MW	10,380 MW
10 Nov, 01:00	10,628 MW	10,060 MW
10 Nov, 02:00	10,416 MW	9,880 MW
10 Nov, 03:00	10,631 MW	9,910 MW
10 Nov, 04:00	10,781 MW	10,220 MW
10 Nov, 05:00	11,271 MW	11,180 MW
10 Nov, 06:00	12,562 MW	12,700 MW
10 Nov, 07:00	12,714 MW	12,980 MW
10 Nov, 08:00	11,887 MW	12,120 MW
10 Nov, 09:00	11,626 MW	11,120 MW
10 Nov, 10:00	11,345 MW	10,980 MW
10 Nov, 11:00	11,151 MW	11,010 MW
10 Nov, 12:00	11,523 MW	10,330 MW
10 Nov, 13:00	11,465 MW	10,840 MW
10 Nov, 14:00	12,017 MW	11,640 MW
10 Nov, 15:00	12,845 MW	12,710 MW
10 Nov, 16:00	13,956 MW	14,020 MW
10 Nov, 17:00	14,667 MW	14,770 MW
10 Nov, 18:00	14,489 MW	14,570 MW
10 Nov, 19:00	14,138 MW	14,190 MW
10 Nov, 20:00	13,569 MW	13,620 MW
10 Nov, 21:00	12,840 MW	12,740 MW
10 Nov, 22:00	11,963 MW	11,790 MW
10 Nov, 23:00	11,126 MW	10,910 MW
11 Nov, 00:00	10,842 MW	10,310 MW
11 Nov, 01:00	10,748 MW	9,930 MW
11 Nov, 02:00	10,920 MW	9,750 MW
11 Nov, 03:00	10,928 MW	9,730 MW
11 Nov, 04:00	11,036 MW	10,020 MW
11 Nov, 05:00	11,553 MW	10,870 MW
11 Nov, 06:00	12,149 MW	12,170 MW
11 Nov, 07:00	12,315 MW	12,390 MW
11 Nov, 08:00	11,271 MW	11,320 MW
11 Nov, 09:00	10,322 MW	9,850 MW
11 Nov, 10:00	10,423 MW	9,590 MW
11 Nov, 11:00	10,227 MW	9,040 MW
11 Nov, 12:00	10,441 MW	9,250 MW
11 Nov, 13:00	11,087 MW	9,960 MW
11 Nov, 14:00	11,727 MW	11,100 MW
11 Nov, 15:00	12,762 MW	12,620 MW
11 Nov, 16:00	13,984 MW	13,950 MW
11 Nov, 17:00	14,694 MW	14,850 MW
11 Nov, 18:00	14,463 MW	14,580 MW
11 Nov, 19:00	14,084 MW	14,240 MW
11 Nov, 20:00	13,585 MW	13,670 MW
11 Nov, 21:00	12,854 MW	12,890 MW
11 Nov, 22:00	11,960 MW	11,890 MW
11 Nov, 23:00	11,288 MW	11,030 MW
12 Nov, 00:00	11,185 MW	10,560 MW
12 Nov, 01:00	11,099 MW	10,170 MW
12 Nov, 02:00	10,992 MW	9,990 MW
12 Nov, 03:00	10,924 MW	9,990 MW
12 Nov, 04:00	11,172 MW	10,300 MW
12 Nov, 05:00	11,856 MW	11,040 MW
12 Nov, 06:00	12,962 MW	12,460 MW
12 Nov, 07:00	13,502 MW	13,320 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). ISO-NE Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/iso-ne/

Plain text

World Power Monitor. ISO-NE 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/iso-ne/

BibTeX

@misc{wpm_forecast_accuracy_iso_ne_2026,
  title = {{ISO-NE 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/iso-ne/}
}

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ISO-NE 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