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

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

The day-ahead demand forecast for NYISO was off by 2.9% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 85% of hours landed within 5% of the reading. Its bias was -2.8%: it ran low on average, an under forecast. The largest miss was 1,450 MW (7.3%) too low at 2 Oct 2026, 16:00 EDT (UTC-04:00). Dates and times are local (America/New_York).

Key Facts

  • The day-ahead demand forecast for NYISO was off by 2.9% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 85% of hours landed within 5% of the reading. Its bias was -2.8%: it ran low on average, an under forecast. The largest miss was 1,450 MW (7.3%) too low at 2 Oct 2026, 16:00 EDT (UTC-04:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, NYISO came 16 (1 is the smallest error).
  • On average the forecast differed from reported demand by 430 MW, against average demand of 14,795 MW.
  • The forecast was above reported demand in 7% of compared hours.

Forecast Error at a Glance

719 hours from 28 September to 28 October 2026
Average error2.9%
Bias-2.8%
Hours within 5%85%
Worst miss1,450 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-412 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 1,450 MW (7.3%) too low at 2 Oct 2026, 16:00 EDT (UTC-04:00): forecast 18,536 MW, reported 19,986 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, 07:00 EDT (UTC-04:00)
NYISO day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for NYISO over the last 7 days of the window, to 28 Oct 2026, 07:00 EDT (UTC-04:00). Gaps are hours with a missing, zero or implausible report. 0 5,000 10,000 15,000 20,000 21 Oct, 08:0022 Oct, 08:0023 Oct, 08:0024 Oct, 08:0025 Oct, 08:0026 Oct, 08:0027 Oct, 08:00
Hourly reported demand and the day-ahead forecast for NYISO over the last 7 days of the window, to 28 Oct 2026, 07:00 EDT (UTC-04:00). 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, 08:0015,981 MW15,017 MW
21 Oct, 09:0014,547 MW13,828 MW
21 Oct, 10:0013,568 MW12,904 MW
21 Oct, 11:0013,267 MW12,332 MW
21 Oct, 12:0013,103 MW12,136 MW
21 Oct, 13:0013,081 MW12,156 MW
21 Oct, 14:0013,298 MW12,325 MW
21 Oct, 15:0013,801 MW12,954 MW
21 Oct, 16:0015,081 MW14,112 MW
21 Oct, 17:0016,675 MW15,699 MW
21 Oct, 18:0017,485 MW16,968 MW
21 Oct, 19:0017,501 MW17,007 MW
21 Oct, 20:0016,958 MW16,542 MW
21 Oct, 21:0016,261 MW15,831 MW
21 Oct, 22:0015,347 MW14,929 MW
21 Oct, 23:0014,455 MW14,010 MW
22 Oct, 00:0013,826 MW13,323 MW
22 Oct, 01:0013,363 MW12,857 MW
22 Oct, 02:0013,113 MW12,575 MW
22 Oct, 03:0012,998 MW12,478 MW
22 Oct, 04:0013,220 MW12,676 MW
22 Oct, 05:0014,027 MW13,415 MW
22 Oct, 06:0015,527 MW14,825 MW
22 Oct, 07:0016,590 MW15,695 MW
22 Oct, 08:0016,123 MW15,274 MW
22 Oct, 09:0014,719 MW14,233 MW
22 Oct, 10:0013,767 MW13,411 MW
22 Oct, 11:0013,339 MW12,968 MW
22 Oct, 12:0013,157 MW12,835 MW
22 Oct, 13:0013,241 MW12,951 MW
22 Oct, 14:0013,457 MW13,218 MW
22 Oct, 15:0014,177 MW13,781 MW
22 Oct, 16:0015,535 MW14,776 MW
22 Oct, 17:0016,911 MW16,069 MW
22 Oct, 18:0017,504 MW17,048 MW
22 Oct, 19:0017,421 MW16,988 MW
22 Oct, 20:0016,931 MW16,486 MW
22 Oct, 21:0016,196 MW15,757 MW
22 Oct, 22:0015,309 MW14,885 MW
22 Oct, 23:0014,438 MW13,981 MW
23 Oct, 00:0013,812 MW13,355 MW
23 Oct, 01:0013,295 MW12,883 MW
23 Oct, 02:0012,983 MW12,600 MW
23 Oct, 03:0012,880 MW12,515 MW
23 Oct, 04:0013,069 MW12,723 MW
23 Oct, 05:0013,807 MW13,473 MW
23 Oct, 06:0015,230 MW14,876 MW
23 Oct, 07:0016,296 MW15,688 MW
23 Oct, 08:0015,879 MW15,172 MW
23 Oct, 09:0014,513 MW13,950 MW
23 Oct, 10:0013,523 MW13,058 MW
23 Oct, 11:0013,104 MW12,594 MW
23 Oct, 12:0012,904 MW12,381 MW
23 Oct, 13:0012,875 MW12,333 MW
23 Oct, 14:0013,007 MW12,544 MW
23 Oct, 15:0013,692 MW13,137 MW
23 Oct, 16:0015,105 MW14,298 MW
23 Oct, 17:0016,484 MW15,768 MW
23 Oct, 18:0017,024 MW16,799 MW
23 Oct, 19:0016,948 MW16,733 MW
23 Oct, 20:0016,577 MW16,314 MW
23 Oct, 21:0016,080 MW15,753 MW
23 Oct, 22:0015,389 MW15,080 MW
23 Oct, 23:0014,596 MW14,317 MW
24 Oct, 00:0014,088 MW13,550 MW
24 Oct, 01:0013,697 MW13,102 MW
24 Oct, 02:0013,415 MW12,821 MW
24 Oct, 03:0013,270 MW12,690 MW
24 Oct, 04:0013,308 MW12,721 MW
24 Oct, 05:0013,632 MW13,035 MW
24 Oct, 06:0014,282 MW13,646 MW
24 Oct, 07:0014,935 MW14,168 MW
24 Oct, 08:0014,710 MW13,879 MW
24 Oct, 09:0013,600 MW12,858 MW
24 Oct, 10:0012,622 MW12,039 MW
24 Oct, 11:0012,110 MW11,568 MW
24 Oct, 12:0011,831 MW11,288 MW
24 Oct, 13:0011,714 MW11,109 MW
24 Oct, 14:0011,772 MW11,149 MW
24 Oct, 15:0012,327 MW11,693 MW
24 Oct, 16:0013,714 MW12,883 MW
24 Oct, 17:0015,343 MW14,450 MW
24 Oct, 18:0016,186 MW15,753 MW
24 Oct, 19:0016,184 MW15,741 MW
24 Oct, 20:0015,947 MW15,456 MW
24 Oct, 21:0015,562 MW15,062 MW
24 Oct, 22:0015,044 MW14,524 MW
24 Oct, 23:0014,447 MW13,897 MW
25 Oct, 00:0013,904 MW13,332 MW
25 Oct, 01:0013,471 MW12,902 MW
25 Oct, 02:0013,200 MW12,615 MW
25 Oct, 03:0013,055 MW12,464 MW
25 Oct, 04:0013,079 MW12,454 MW
25 Oct, 05:0013,322 MW12,671 MW
25 Oct, 06:0013,843 MW13,113 MW
25 Oct, 07:0014,379 MW13,367 MW
25 Oct, 08:0014,110 MW12,830 MW
25 Oct, 09:0012,863 MW11,745 MW
25 Oct, 10:0012,009 MW10,961 MW
25 Oct, 11:0011,710 MW10,616 MW
25 Oct, 12:0011,623 MW10,575 MW
25 Oct, 13:0011,624 MW10,636 MW
25 Oct, 14:0011,814 MW10,978 MW
25 Oct, 15:0012,501 MW11,688 MW
25 Oct, 16:0014,039 MW13,059 MW
25 Oct, 17:0015,777 MW14,711 MW
25 Oct, 18:0016,582 MW15,918 MW
25 Oct, 19:0016,618 MW15,902 MW
25 Oct, 20:0016,241 MW15,582 MW
25 Oct, 21:0015,655 MW15,034 MW
25 Oct, 22:0014,947 MW14,335 MW
25 Oct, 23:0014,150 MW13,603 MW
26 Oct, 00:0013,610 MW13,170 MW
26 Oct, 01:0013,214 MW12,744 MW
26 Oct, 02:0012,952 MW12,511 MW
26 Oct, 03:0012,886 MW12,453 MW
26 Oct, 04:0013,153 MW12,682 MW
26 Oct, 05:0013,981 MW13,494 MW
26 Oct, 06:0015,498 MW14,982 MW
26 Oct, 07:0016,606 MW16,048 MW
26 Oct, 08:0016,359 MW15,842 MW
26 Oct, 09:0015,198 MW14,812 MW
26 Oct, 10:0014,326 MW14,122 MW
26 Oct, 11:0013,824 MW13,851 MW
26 Oct, 12:0013,790 MW13,806 MW
26 Oct, 13:0013,972 MW13,902 MW
26 Oct, 14:0014,454 MW14,092 MW
26 Oct, 15:0015,449 MW14,536 MW
26 Oct, 16:0016,548 MW15,532 MW
26 Oct, 17:0017,447 MW16,788 MW
26 Oct, 18:0017,838 MW17,538 MW
26 Oct, 19:0017,589 MW17,352 MW
26 Oct, 20:0017,003 MW16,752 MW
26 Oct, 21:0016,182 MW15,935 MW
26 Oct, 22:0015,226 MW14,986 MW
26 Oct, 23:0014,284 MW14,055 MW
27 Oct, 00:0013,619 MW13,473 MW
27 Oct, 01:0013,153 MW12,987 MW
27 Oct, 02:0012,862 MW12,689 MW
27 Oct, 03:0012,744 MW12,580 MW
27 Oct, 04:0012,952 MW12,773 MW
27 Oct, 05:0013,723 MW13,535 MW
27 Oct, 06:0015,249 MW15,021 MW
27 Oct, 07:0016,346 MW16,052 MW
27 Oct, 08:0016,040 MW15,730 MW
27 Oct, 09:0014,649 MW14,526 MW
27 Oct, 10:0013,658 MW13,680 MW
27 Oct, 11:0013,284 MW13,229 MW
27 Oct, 12:0013,100 MW12,985 MW
27 Oct, 13:0013,099 MW12,946 MW
27 Oct, 14:0013,240 MW13,015 MW
27 Oct, 15:0013,930 MW13,514 MW
27 Oct, 16:0015,451 MW14,811 MW
27 Oct, 17:0017,000 MW16,433 MW
27 Oct, 18:0017,703 MW17,463 MW
27 Oct, 19:0017,580 MW17,405 MW
27 Oct, 20:0017,139 MW16,915 MW
27 Oct, 21:0016,438 MW16,185 MW
27 Oct, 22:0015,453 MW15,308 MW
27 Oct, 23:0014,560 MW14,444 MW
28 Oct, 00:0013,977 MW13,654 MW
28 Oct, 01:0013,545 MW13,221 MW
28 Oct, 02:0013,279 MW12,960 MW
28 Oct, 03:0013,197 MW12,877 MW
28 Oct, 04:0013,411 MW13,089 MW
28 Oct, 05:0014,189 MW13,868 MW
28 Oct, 06:0015,666 MW15,319 MW
28 Oct, 07:0016,722 MW16,410 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). NYISO Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/nyiso/

Plain text

World Power Monitor. NYISO 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/nyiso/

BibTeX 
@misc{wpm_forecast_accuracy_nyiso_2026,
  title = {{NYISO 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/nyiso/}
}

Permalink: https://worldpowermonitor.com/forecast-accuracy/nyiso/

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