Was the forecast right for Boston on Tue Sep 22?
Boston, Massachusetts · daily high temperature in °F · forecasts from each model's archived runs, verified against the BOS observations
14 days out, 4 models put Boston's Tue Sep 22 high anywhere from 65° to 67°;by the final call, the day before, the field had settled to a median of 62°. The day verified at 63° against the BOS observations — drizzle.
ICON landed closest, off by 0.5°. AIGFS ran 4° cool.
What every model said, at every lead
Daily-high calls for Tue Sep 22 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 · 2026-09-07 | — | 60° | — | — | 74° | — | — | 60–74° |
| 14d · 2026-09-08 | 67° | 67° | 65° | — | 65° | — | — | 65–67° |
| 13d · 2026-09-09 | 81° | 58° | 62° | — | 66° | — | — | 58–81° |
| 12d · 2026-09-10 | 60° | 62° | 61° | — | 59° | — | — | 59–62° |
| 11d · 2026-09-11 | 63° | 65° | 64° | — | 60° | — | — | 60–65° |
| 10d · 2026-09-12 | 64° | 64° | 65° | — | 62° | — | — | 62–65° |
| 9d · 2026-09-13 | 65° | 66° | 82° | 67° | 57° | — | — | 57–82° |
| 8d · 2026-09-14 | 58° | 60° | 61° | 64° | 61° | — | — | 58–64° |
| 7d · 2026-09-15 | 61° | 62° | 61° | 60° | 60° | — | — | 60–62° |
| 6d · 2026-09-16 | 59° | 59° | 63° | 59° | 59° | 62° | 64° | 59–64° |
| 5d · 2026-09-17 | 60° | 56° | 62° | 58° | 62° | 63° | 61° | 56–63° |
| 4d · 2026-09-18 | 60° | 59° | 59° | 58° | 58° | 62° | 61° | 58–62° |
| 3d · 2026-09-19 | 61° | 59° | 60° | 60° | 58° | 63° | 61° | 58–63° |
| 2d · 2026-09-20 | 61° | 59° | 61° | 62° | 59° | 63° | 62° | 59–63° |
| 1d · 2026-09-21 | 62° | 59° | 61° | 64° | 60° | 62° | 62° | 59–64° |
| actual | 63° |
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. Archive depth varies by city; receipts exist only for dates the archive watched arrive.