Was the forecast right for Boston on Tue Sep 29?
Boston, Massachusetts · daily high temperature in °C · forecasts from each model's archived runs, verified against the BOS observations
14 days out, 4 models put Boston's Tue Sep 29 high anywhere from 19° to 26°;by the final call, the day before, the field had settled to a median of 18°. The day verified at 19° against the BOS observations — drizzle.
UKMO landed closest, off by 0.3°.
What every model said, at every lead
Daily-high calls for Tue Sep 29 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 · 2026-09-14 | — | 20° | — | — | 13° | — | — | 13–20° |
| 14d · 2026-09-15 | 22° | 21° | 19° | — | 26° | — | — | 19–26° |
| 13d · 2026-09-16 | 20° | 17° | 14° | — | 24° | — | — | 14–24° |
| 12d · 2026-09-17 | 15° | 26° | 19° | — | 16° | — | — | 15–26° |
| 11d · 2026-09-18 | 18° | 20° | 23° | — | 17° | — | — | 17–23° |
| 10d · 2026-09-19 | 20° | 23° | 20° | — | 15° | — | — | 15–23° |
| 9d · 2026-09-20 | 20° | 21° | 18° | 19° | 16° | — | — | 16–21° |
| 8d · 2026-09-21 | 20° | 25° | 15° | 18° | 18° | — | — | 15–25° |
| 7d · 2026-09-22 | 21° | 21° | 16° | 19° | 17° | — | — | 16–21° |
| 6d · 2026-09-23 | 17° | 21° | 17° | 20° | 16° | 16° | 16° | 16–21° |
| 5d · 2026-09-24 | 20° | 17° | 18° | 18° | 17° | 19° | 21° | 17–21° |
| 4d · 2026-09-25 | 19° | 18° | 20° | 17° | 16° | 16° | 17° | 16–20° |
| 3d · 2026-09-26 | 18° | 15° | 17° | 18° | 14° | 17° | 19° | 14–19° |
| 2d · 2026-09-27 | 18° | 15° | 18° | 17° | 17° | 16° | 20° | 15–20° |
| 1d · 2026-09-28 | 18° | 18° | 20° | 20° | 18° | 18° | 19° | 18–20° |
| actual | 19° |
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.