IID Demand Forecast Accuracy: Error, Bias and Worst Miss, 6 October to 5 November 2026

The day-ahead demand forecast for IID was off by 5.1% on average (mean absolute percentage error) over 695 hours from 6 October to 5 November 2026, and 73% of hours landed within 5% of the reading. Its bias was +2.1%: it ran high on average, an over forecast. The largest miss was 275 MW (73.7%) too high at 11 Oct 2026, 14:00 PDT (UTC-07:00). Dates and times are local (America/Los_Angeles).

Key Facts

The day-ahead demand forecast for IID was off by 5.1% on average (mean absolute percentage error) over 695 hours from 6 October to 5 November 2026, and 73% of hours landed within 5% of the reading. Its bias was +2.1%: it ran high on average, an over forecast. The largest miss was 275 MW (73.7%) too high at 11 Oct 2026, 14:00 PDT (UTC-07:00).
Across 53 US grids ranked by average error over their own latest 30 day windows, IID came 35 (1 is the smallest error).
On average the forecast differed from reported demand by 19 MW, against average demand of 387 MW.
The forecast was above reported demand in 54% of compared hours.

Forecast Error at a Glance

695 hours from 6 October to 5 November 2026

Average error5.1%

Bias+2.1%

Hours within 5%73%

Worst miss275 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+8 MW per hour on average): the forecast ran high on average, an over forecast. The worst miss was 275 MW (73.7%) too high at 11 Oct 2026, 14:00 PDT (UTC-07:00): forecast 648 MW, reported 373 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, 05:00 PST (UTC-08:00)

Hourly reported demand and the day-ahead forecast for IID over the last 7 days of the window, to 5 Nov 2026, 05:00 PST (UTC-08:00). Gaps are hours with a missing, zero or implausible report.

Data to 2026-11-05

Show the data table (168 rows)

Local hour	Reported demand	Day-ahead forecast
29 Oct, 07:00	322 MW	318 MW
29 Oct, 08:00	323 MW	324 MW
29 Oct, 09:00	344 MW	331 MW
29 Oct, 10:00	351 MW	344 MW
29 Oct, 11:00	362 MW	358 MW
29 Oct, 12:00	390 MW	384 MW
29 Oct, 13:00	432 MW	411 MW
29 Oct, 14:00	455 MW	440 MW
29 Oct, 15:00	483 MW	463 MW
29 Oct, 16:00	485 MW	474 MW
29 Oct, 17:00	470 MW	475 MW
29 Oct, 18:00	457 MW	462 MW
29 Oct, 19:00	438 MW	443 MW
29 Oct, 20:00	413 MW	417 MW
29 Oct, 21:00	400 MW	389 MW
29 Oct, 22:00	358 MW	361 MW
29 Oct, 23:00	333 MW	330 MW
30 Oct, 00:00	305 MW	305 MW
30 Oct, 01:00	290 MW	293 MW
30 Oct, 02:00	284 MW	278 MW
30 Oct, 03:00	276 MW	275 MW
30 Oct, 04:00	285 MW	279 MW
30 Oct, 05:00	303 MW	297 MW
30 Oct, 06:00	328 MW	325 MW
30 Oct, 07:00	344 MW	331 MW
30 Oct, 08:00	369 MW	342 MW
30 Oct, 09:00	356 MW	350 MW
30 Oct, 10:00	365 MW	358 MW
30 Oct, 11:00	369 MW	372 MW
30 Oct, 12:00	374 MW	393 MW
30 Oct, 13:00	399 MW	416 MW
30 Oct, 14:00	418 MW	433 MW
30 Oct, 15:00	431 MW	447 MW
30 Oct, 16:00	432 MW	447 MW
30 Oct, 17:00	422 MW	444 MW
30 Oct, 18:00	407 MW	426 MW
30 Oct, 19:00	384 MW	409 MW
30 Oct, 20:00	365 MW	385 MW
30 Oct, 21:00	350 MW	366 MW
30 Oct, 22:00	323 MW	340 MW
30 Oct, 23:00	299 MW	312 MW
31 Oct, 00:00	285 MW	n/a
31 Oct, 01:00	269 MW	n/a
31 Oct, 02:00	259 MW	n/a
31 Oct, 03:00	253 MW	n/a
31 Oct, 04:00	245 MW	n/a
31 Oct, 05:00	256 MW	n/a
31 Oct, 06:00	274 MW	n/a
31 Oct, 07:00	270 MW	n/a
31 Oct, 08:00	292 MW	n/a
31 Oct, 09:00	299 MW	n/a
31 Oct, 10:00	305 MW	n/a
31 Oct, 11:00	325 MW	n/a
31 Oct, 12:00	324 MW	n/a
31 Oct, 13:00	347 MW	n/a
31 Oct, 14:00	362 MW	n/a
31 Oct, 15:00	388 MW	n/a
31 Oct, 16:00	380 MW	n/a
31 Oct, 17:00	369 MW	n/a
31 Oct, 18:00	363 MW	n/a
31 Oct, 19:00	348 MW	n/a
31 Oct, 20:00	328 MW	n/a
31 Oct, 21:00	323 MW	n/a
31 Oct, 22:00	310 MW	n/a
31 Oct, 23:00	289 MW	n/a
1 Nov, 00:00	277 MW	278 MW
1 Nov, 01:00	251 MW	264 MW
1 Nov, 01:00	250 MW	264 MW
1 Nov, 02:00	246 MW	257 MW
1 Nov, 03:00	253 MW	251 MW
1 Nov, 04:00	258 MW	253 MW
1 Nov, 05:00	267 MW	254 MW
1 Nov, 06:00	272 MW	259 MW
1 Nov, 07:00	280 MW	264 MW
1 Nov, 08:00	286 MW	271 MW
1 Nov, 09:00	298 MW	279 MW
1 Nov, 10:00	313 MW	283 MW
1 Nov, 11:00	338 MW	284 MW
1 Nov, 12:00	347 MW	295 MW
1 Nov, 13:00	355 MW	315 MW
1 Nov, 14:00	352 MW	335 MW
1 Nov, 15:00	360 MW	347 MW
1 Nov, 16:00	355 MW	350 MW
1 Nov, 17:00	342 MW	357 MW
1 Nov, 18:00	333 MW	349 MW
1 Nov, 19:00	318 MW	336 MW
1 Nov, 20:00	297 MW	326 MW
1 Nov, 21:00	280 MW	314 MW
1 Nov, 22:00	261 MW	301 MW
1 Nov, 23:00	248 MW	280 MW
2 Nov, 00:00	248 MW	259 MW
2 Nov, 01:00	235 MW	250 MW
2 Nov, 02:00	238 MW	245 MW
2 Nov, 03:00	231 MW	243 MW
2 Nov, 04:00	242 MW	253 MW
2 Nov, 05:00	254 MW	267 MW
2 Nov, 06:00	274 MW	292 MW
2 Nov, 07:00	276 MW	302 MW
2 Nov, 08:00	291 MW	305 MW
2 Nov, 09:00	285 MW	308 MW
2 Nov, 10:00	304 MW	312 MW
2 Nov, 11:00	299 MW	317 MW
2 Nov, 12:00	335 MW	334 MW
2 Nov, 13:00	365 MW	358 MW
2 Nov, 14:00	382 MW	383 MW
2 Nov, 15:00	411 MW	397 MW
2 Nov, 16:00	412 MW	405 MW
2 Nov, 17:00	400 MW	401 MW
2 Nov, 18:00	391 MW	384 MW
2 Nov, 19:00	364 MW	364 MW
2 Nov, 20:00	350 MW	347 MW
2 Nov, 21:00	340 MW	333 MW
2 Nov, 22:00	305 MW	318 MW
2 Nov, 23:00	278 MW	294 MW
3 Nov, 00:00	259 MW	264 MW
3 Nov, 01:00	252 MW	250 MW
3 Nov, 02:00	254 MW	246 MW
3 Nov, 03:00	249 MW	243 MW
3 Nov, 04:00	252 MW	251 MW
3 Nov, 05:00	272 MW	268 MW
3 Nov, 06:00	280 MW	293 MW
3 Nov, 07:00	293 MW	299 MW
3 Nov, 08:00	296 MW	302 MW
3 Nov, 09:00	304 MW	299 MW
3 Nov, 10:00	309 MW	302 MW
3 Nov, 11:00	321 MW	312 MW
3 Nov, 12:00	327 MW	328 MW
3 Nov, 13:00	353 MW	345 MW
3 Nov, 14:00	377 MW	362 MW
3 Nov, 15:00	401 MW	377 MW
3 Nov, 16:00	405 MW	394 MW
3 Nov, 17:00	401 MW	404 MW
3 Nov, 18:00	380 MW	396 MW
3 Nov, 19:00	366 MW	379 MW
3 Nov, 20:00	350 MW	359 MW
3 Nov, 21:00	330 MW	340 MW
3 Nov, 22:00	308 MW	314 MW
3 Nov, 23:00	288 MW	290 MW
4 Nov, 00:00	268 MW	266 MW
4 Nov, 01:00	254 MW	253 MW
4 Nov, 02:00	252 MW	248 MW
4 Nov, 03:00	250 MW	246 MW
4 Nov, 04:00	260 MW	258 MW
4 Nov, 05:00	276 MW	275 MW
4 Nov, 06:00	291 MW	289 MW
4 Nov, 07:00	301 MW	297 MW
4 Nov, 08:00	302 MW	308 MW
4 Nov, 09:00	312 MW	300 MW
4 Nov, 10:00	318 MW	314 MW
4 Nov, 11:00	332 MW	316 MW
4 Nov, 12:00	349 MW	335 MW
4 Nov, 13:00	384 MW	358 MW
4 Nov, 14:00	410 MW	383 MW
4 Nov, 15:00	423 MW	406 MW
4 Nov, 16:00	431 MW	420 MW
4 Nov, 17:00	429 MW	409 MW
4 Nov, 18:00	398 MW	392 MW
4 Nov, 19:00	377 MW	377 MW
4 Nov, 20:00	361 MW	366 MW
4 Nov, 21:00	335 MW	347 MW
4 Nov, 22:00	306 MW	317 MW
4 Nov, 23:00	281 MW	284 MW
5 Nov, 00:00	298 MW	270 MW
5 Nov, 01:00	298 MW	258 MW
5 Nov, 02:00	298 MW	251 MW
5 Nov, 03:00	298 MW	249 MW
5 Nov, 04:00	298 MW	259 MW
5 Nov, 05:00	298 MW	261 MW

Assumptions

Only hours with both a forecast and a positive demand reading count (695 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). IID Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/iid/

Plain text

World Power Monitor. IID 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/iid/

BibTeX

@misc{wpm_forecast_accuracy_iid_2026,
  title = {{IID 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/iid/}
}

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

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IID Demand Forecast Accuracy: Error, Bias and Worst Miss, 6 October to 5 November 2026

Key Facts

Forecast Error at a Glance

Forecast and Reported Demand, Last 7 Days

Assumptions

Related