Was the forecast right for Boston on Tue Oct 20?
Boston, Massachusetts · daily high temperature in °C · forecasts from each model's archived runs, verified against the BOS observations
13 days out, 4 models put Boston's Tue Oct 20 high anywhere from 11° to 23°;by the final call, the day before, the field had settled to a median of 16°. The day verified at 17° against the BOS observations — cloudy.
ICON landed closest, off by 0.0°. ECMWF ran 2° cool.
What every model said, at every lead
Daily-high calls for Tue Oct 20 as each model's runs approached it — the last archived run per day. NBM and The Spread's own blend are consensus products and stay out of these ranges and rankings; the Boston scoreboard shows them, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-10-05 | — | 10° | — | — | 17° | — | — | 10–17° |
| 14d · 2026-10-06 | 17° | 17° | — | — | 17° | — | — | 17–17° |
| 13d · 2026-10-07 | 23° | 16° | 11° | — | 14° | — | — | 11–23° |
| 12d · 2026-10-08 | 14° | 15° | 12° | — | 12° | — | — | 12–15° |
| 11d · 2026-10-09 | 19° | 17° | 15° | — | 11° | — | — | 11–19° |
| 10d · 2026-10-10 | 19° | 16° | 20° | — | 12° | — | — | 12–20° |
| 9d · 2026-10-11 | 20° | 20° | 20° | 17° | 19° | — | — | 17–20° |
| 8d · 2026-10-12 | — | 18° | 19° | 16° | 18° | — | — | 16–19° |
| 7d · 2026-10-13 | 19° | 21° | 20° | 17° | 18° | — | — | 17–21° |
| 6d · 2026-10-14 | 16° | 18° | 14° | 17° | 19° | 15° | 15° | 14–19° |
| 5d · 2026-10-15 | 15° | 16° | 15° | 14° | 14° | 15° | 15° | 14–16° |
| 4d · 2026-10-16 | 16° | 14° | 14° | 13° | 15° | 15° | 16° | 13–16° |
| 3d · 2026-10-17 | 15° | 15° | 14° | 14° | 14° | 16° | 15° | 14–16° |
| 2d · 2026-10-18 | 15° | 15° | 14° | 16° | 14° | 17° | 15° | 14–17° |
| 1d · 2026-10-19 | 16° | 16° | 14° | 16° | 14° | 17° | 15° | 14–17° |
| actual | 17° |
Read it honestly
This is one date, not a league table. A model can win a day it deserved to lose; rankings only mean something over a window. For that, see which model has been most accurate in Boston — or every city The Spread scores.
Forecasts are what each model's archived runs said at the time, captured at The Spread's sweep times — never reconstructed after the fact. Truth is the BOS observations. The actual values are the ones in hand when this receipt was settled, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; receipts exist only for dates the archive watched arrive.