Italy Sicily Demand Forecast Accuracy: Error, Bias and Worst Miss, 23 August to 20 September 2026
The day-ahead demand forecast for Italy Sicily was off by 4.4% on average (mean absolute percentage error) over 686 hours from 23 August to 20 September 2026, and 65% of hours landed within 5% of the reading. Its bias was -0.1%: it ran close to balanced on average. The largest miss was 545 MW (15.2%) too low at 26 Aug 2026, 19:00 CEST (UTC+02:00). Dates and times are local (Europe/Rome).
Key Facts
- The day-ahead demand forecast for Italy Sicily was off by 4.4% on average (mean absolute percentage error) over 686 hours from 23 August to 20 September 2026, and 65% of hours landed within 5% of the reading. Its bias was -0.1%: it ran close to balanced on average. The largest miss was 545 MW (15.2%) too low at 26 Aug 2026, 19:00 CEST (UTC+02:00).
- Across 47 European bidding zones ranked by average error over their own latest 30 day windows, Italy Sicily came 29 (1 is the smallest error).
- On average the forecast differed from reported demand by 116 MW, against average demand of 2,512 MW.
- The forecast was above reported demand in 51% of compared hours.
Forecast Error at a Glance
686 hours from 23 August to 20 September 2026Average error4.4%
Bias-0.1%
Hours within 5%65%
Worst miss545 MW
Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-16 MW per hour on average): the forecast ran close to balanced on average. The worst miss was 545 MW (15.2%) too low at 26 Aug 2026, 19:00 CEST (UTC+02:00): forecast 3,048 MW, reported 3,592 MW.
Source: ENTSO-E Transparency Platform (transparency.entsoe.eu), CC BY 4.0. Aggregated and converted by World Power Monitor; ENTSO-E does not endorse this site. (ENTSO-E Terms of Use plus CC BY 4.0 for listed data items) Data as of 2026-09-20. 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 20 Sept 2026, 13:00 CEST (UTC+02:00)Data to 2026-09-20
| Local hour | Reported demand | Day-ahead forecast |
|---|---|---|
| 13 Sept, 14:00 | 2,055 MW | 2,043 MW |
| 13 Sept, 15:00 | 1,985 MW | 1,998 MW |
| 13 Sept, 16:00 | 2,016 MW | 2,008 MW |
| 13 Sept, 17:00 | 2,049 MW | 2,088 MW |
| 13 Sept, 18:00 | 2,122 MW | 2,158 MW |
| 13 Sept, 19:00 | 2,296 MW | 2,223 MW |
| 13 Sept, 20:00 | 2,370 MW | 2,268 MW |
| 13 Sept, 21:00 | 2,258 MW | 2,213 MW |
| 13 Sept, 22:00 | 2,133 MW | 2,143 MW |
| 13 Sept, 23:00 | 1,996 MW | 2,020 MW |
| 14 Sept, 00:00 | 1,838 MW | 1,925 MW |
| 14 Sept, 01:00 | 1,725 MW | 1,795 MW |
| 14 Sept, 02:00 | 1,664 MW | 1,718 MW |
| 14 Sept, 03:00 | 1,630 MW | 1,703 MW |
| 14 Sept, 04:00 | 1,611 MW | 1,675 MW |
| 14 Sept, 05:00 | 1,661 MW | 1,705 MW |
| 14 Sept, 06:00 | 1,782 MW | 1,770 MW |
| 14 Sept, 07:00 | 1,960 MW | 1,973 MW |
| 14 Sept, 08:00 | 2,175 MW | 2,213 MW |
| 14 Sept, 09:00 | 2,276 MW | 2,250 MW |
| 14 Sept, 10:00 | 2,271 MW | 2,280 MW |
| 14 Sept, 11:00 | 2,264 MW | 2,285 MW |
| 14 Sept, 12:00 | 2,257 MW | 2,253 MW |
| 14 Sept, 13:00 | 2,260 MW | 2,210 MW |
| 14 Sept, 14:00 | 2,294 MW | 2,173 MW |
| 14 Sept, 15:00 | 2,338 MW | 2,220 MW |
| 14 Sept, 16:00 | 2,377 MW | 2,315 MW |
| 14 Sept, 17:00 | 2,362 MW | 2,388 MW |
| 14 Sept, 18:00 | 2,365 MW | 2,405 MW |
| 14 Sept, 19:00 | 2,518 MW | 2,495 MW |
| 14 Sept, 20:00 | 2,536 MW | 2,468 MW |
| 14 Sept, 21:00 | 2,385 MW | 2,345 MW |
| 14 Sept, 22:00 | 2,221 MW | 2,218 MW |
| 14 Sept, 23:00 | 2,030 MW | 2,070 MW |
| 15 Sept, 00:00 | 1,847 MW | 1,935 MW |
| 15 Sept, 01:00 | 1,742 MW | 1,828 MW |
| 15 Sept, 02:00 | 1,692 MW | 1,750 MW |
| 15 Sept, 03:00 | 1,665 MW | 1,713 MW |
| 15 Sept, 04:00 | 1,664 MW | 1,703 MW |
| 15 Sept, 05:00 | 1,711 MW | 1,728 MW |
| 15 Sept, 06:00 | 1,833 MW | 1,833 MW |
| 15 Sept, 07:00 | 2,018 MW | 2,010 MW |
| 15 Sept, 08:00 | 2,114 MW | 2,190 MW |
| 15 Sept, 09:00 | 2,264 MW | 2,303 MW |
| 15 Sept, 10:00 | 2,251 MW | 2,258 MW |
| 15 Sept, 11:00 | 2,215 MW | 2,238 MW |
| 15 Sept, 12:00 | 2,293 MW | 2,253 MW |
| 15 Sept, 13:00 | 2,230 MW | 2,285 MW |
| 15 Sept, 14:00 | 2,171 MW | 2,323 MW |
| 15 Sept, 15:00 | 2,173 MW | 2,383 MW |
| 15 Sept, 16:00 | 2,325 MW | 2,415 MW |
| 15 Sept, 17:00 | 2,290 MW | 2,490 MW |
| 15 Sept, 18:00 | 2,323 MW | 2,513 MW |
| 15 Sept, 19:00 | 2,478 MW | 2,633 MW |
| 15 Sept, 20:00 | 2,455 MW | 2,623 MW |
| 15 Sept, 21:00 | 2,281 MW | 2,480 MW |
| 15 Sept, 22:00 | 2,112 MW | 2,320 MW |
| 15 Sept, 23:00 | 1,932 MW | 2,140 MW |
| 16 Sept, 00:00 | 1,772 MW | 1,948 MW |
| 16 Sept, 01:00 | 1,672 MW | 1,838 MW |
| 16 Sept, 02:00 | 1,610 MW | 1,763 MW |
| 16 Sept, 03:00 | 1,580 MW | 1,723 MW |
| 16 Sept, 04:00 | 1,586 MW | 1,713 MW |
| 16 Sept, 05:00 | 1,638 MW | 1,755 MW |
| 16 Sept, 06:00 | 1,782 MW | 1,843 MW |
| 16 Sept, 07:00 | 1,978 MW | 2,043 MW |
| 16 Sept, 08:00 | 2,144 MW | 2,243 MW |
| 16 Sept, 09:00 | 2,254 MW | 2,330 MW |
| 16 Sept, 10:00 | 2,228 MW | 2,285 MW |
| 16 Sept, 11:00 | 2,230 MW | 2,270 MW |
| 16 Sept, 12:00 | 2,260 MW | 2,288 MW |
| 16 Sept, 13:00 | 2,172 MW | 2,293 MW |
| 16 Sept, 14:00 | 2,157 MW | 2,330 MW |
| 16 Sept, 15:00 | 2,180 MW | 2,390 MW |
| 16 Sept, 16:00 | 2,315 MW | 2,440 MW |
| 16 Sept, 17:00 | 2,343 MW | 2,510 MW |
| 16 Sept, 18:00 | 2,346 MW | 2,553 MW |
| 16 Sept, 19:00 | 2,494 MW | 2,718 MW |
| 16 Sept, 20:00 | 2,487 MW | 2,695 MW |
| 16 Sept, 21:00 | 2,306 MW | 2,535 MW |
| 16 Sept, 22:00 | 2,135 MW | 2,388 MW |
| 16 Sept, 23:00 | 1,956 MW | 2,193 MW |
| 17 Sept, 00:00 | 1,795 MW | 1,908 MW |
| 17 Sept, 01:00 | 1,718 MW | 1,775 MW |
| 17 Sept, 02:00 | 1,640 MW | 1,718 MW |
| 17 Sept, 03:00 | 1,592 MW | 1,685 MW |
| 17 Sept, 04:00 | 1,594 MW | 1,668 MW |
| 17 Sept, 05:00 | 1,637 MW | 1,705 MW |
| 17 Sept, 06:00 | 1,774 MW | 1,785 MW |
| 17 Sept, 07:00 | 1,941 MW | 1,983 MW |
| 17 Sept, 08:00 | 2,113 MW | 2,223 MW |
| 17 Sept, 09:00 | 2,248 MW | 2,298 MW |
| 17 Sept, 10:00 | 2,178 MW | 2,243 MW |
| 17 Sept, 11:00 | 2,186 MW | 2,233 MW |
| 17 Sept, 12:00 | 2,164 MW | 2,200 MW |
| 17 Sept, 13:00 | 2,126 MW | 2,183 MW |
| 17 Sept, 14:00 | 2,183 MW | 2,213 MW |
| 17 Sept, 15:00 | 2,199 MW | 2,263 MW |
| 17 Sept, 16:00 | 2,271 MW | 2,310 MW |
| 17 Sept, 17:00 | 2,422 MW | 2,303 MW |
| 17 Sept, 18:00 | 2,469 MW | 2,323 MW |
| 17 Sept, 19:00 | 2,606 MW | 2,520 MW |
| 17 Sept, 20:00 | 2,579 MW | 2,510 MW |
| 17 Sept, 21:00 | 2,406 MW | 2,360 MW |
| 17 Sept, 22:00 | 2,261 MW | 2,225 MW |
| 17 Sept, 23:00 | 2,085 MW | 2,025 MW |
| 18 Sept, 00:00 | 1,848 MW | 1,835 MW |
| 18 Sept, 01:00 | 1,741 MW | 1,750 MW |
| 18 Sept, 02:00 | 1,675 MW | 1,693 MW |
| 18 Sept, 03:00 | 1,632 MW | 1,655 MW |
| 18 Sept, 04:00 | 1,610 MW | 1,655 MW |
| 18 Sept, 05:00 | 1,673 MW | 1,713 MW |
| 18 Sept, 06:00 | 1,808 MW | 1,803 MW |
| 18 Sept, 07:00 | 2,005 MW | 2,015 MW |
| 18 Sept, 08:00 | 2,205 MW | 2,280 MW |
| 18 Sept, 09:00 | 2,308 MW | 2,373 MW |
| 18 Sept, 10:00 | 2,294 MW | 2,363 MW |
| 18 Sept, 11:00 | 2,262 MW | 2,335 MW |
| 18 Sept, 12:00 | 2,266 MW | 2,325 MW |
| 18 Sept, 13:00 | 2,224 MW | 2,275 MW |
| 18 Sept, 14:00 | 2,114 MW | 2,255 MW |
| 18 Sept, 15:00 | 2,090 MW | 2,250 MW |
| 18 Sept, 16:00 | 2,238 MW | 2,335 MW |
| 18 Sept, 17:00 | 2,434 MW | 2,378 MW |
| 18 Sept, 18:00 | 2,493 MW | 2,403 MW |
| 18 Sept, 19:00 | 2,622 MW | 2,540 MW |
| 18 Sept, 20:00 | 2,549 MW | 2,510 MW |
| 18 Sept, 21:00 | 2,384 MW | 2,348 MW |
| 18 Sept, 22:00 | 2,206 MW | 2,195 MW |
| 18 Sept, 23:00 | 2,051 MW | 2,015 MW |
| 19 Sept, 00:00 | 1,808 MW | 1,905 MW |
| 19 Sept, 01:00 | 1,710 MW | 1,810 MW |
| 19 Sept, 02:00 | 1,664 MW | 1,715 MW |
| 19 Sept, 03:00 | 1,606 MW | 1,668 MW |
| 19 Sept, 04:00 | 1,594 MW | 1,678 MW |
| 19 Sept, 05:00 | 1,619 MW | 1,713 MW |
| 19 Sept, 06:00 | 1,702 MW | 1,768 MW |
| 19 Sept, 07:00 | 1,802 MW | 1,920 MW |
| 19 Sept, 08:00 | 2,020 MW | 2,115 MW |
| 19 Sept, 09:00 | 2,165 MW | 2,220 MW |
| 19 Sept, 10:00 | 2,256 MW | 2,150 MW |
| 19 Sept, 11:00 | 2,268 MW | 2,173 MW |
| 19 Sept, 12:00 | 2,272 MW | 2,175 MW |
| 19 Sept, 13:00 | 2,186 MW | 2,135 MW |
| 19 Sept, 14:00 | 2,100 MW | 2,123 MW |
| 19 Sept, 15:00 | 2,043 MW | 2,133 MW |
| 19 Sept, 16:00 | 2,046 MW | 2,190 MW |
| 19 Sept, 17:00 | 2,095 MW | 2,298 MW |
| 19 Sept, 18:00 | 2,114 MW | 2,330 MW |
| 19 Sept, 19:00 | 2,333 MW | 2,448 MW |
| 19 Sept, 20:00 | 2,281 MW | 2,425 MW |
| 19 Sept, 21:00 | 2,100 MW | 2,255 MW |
| 19 Sept, 22:00 | 1,971 MW | 2,090 MW |
| 19 Sept, 23:00 | 1,833 MW | 1,955 MW |
| 20 Sept, 00:00 | 1,808 MW | 1,855 MW |
| 20 Sept, 01:00 | 1,696 MW | 1,778 MW |
| 20 Sept, 02:00 | 1,622 MW | 1,675 MW |
| 20 Sept, 03:00 | 1,566 MW | 1,638 MW |
| 20 Sept, 04:00 | 1,524 MW | 1,638 MW |
| 20 Sept, 05:00 | 1,549 MW | 1,635 MW |
| 20 Sept, 06:00 | 1,597 MW | 1,650 MW |
| 20 Sept, 07:00 | 1,628 MW | 1,678 MW |
| 20 Sept, 08:00 | 1,798 MW | 1,838 MW |
| 20 Sept, 09:00 | 1,978 MW | 1,985 MW |
| 20 Sept, 10:00 | 1,934 MW | 1,975 MW |
| 20 Sept, 11:00 | 2,005 MW | 1,993 MW |
| 20 Sept, 12:00 | 2,076 MW | 1,958 MW |
| 20 Sept, 13:00 | 1,917 MW | 1,938 MW |
Assumptions
- Only hours with both a forecast and a positive demand reading count (686 of 686 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.
- European figures are for the ENTSO-E bidding zone named on this page. US and European grids are ranked separately.