Was the forecast right for Boston on Wed Sep 23?
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 Wed Sep 23 high anywhere from 57° to 77°;by the final call, the day before, the field had settled to a median of 62°. The day verified at 64° against the BOS observations — cloudy.
GEM landed closest, off by 0.3°. GFS ran 4° cool.
What every model said, at every lead
Daily-high calls for Wed Sep 23 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 · 2026-09-08 | — | 60° | — | — | 62° | — | — | 60–62° |
| 14d · 2026-09-09 | 77° | 57° | 60° | — | 64° | — | — | 57–77° |
| 13d · 2026-09-10 | 65° | 66° | 57° | — | 61° | — | — | 57–66° |
| 12d · 2026-09-11 | 62° | 72° | 61° | — | 61° | — | — | 61–72° |
| 11d · 2026-09-12 | 64° | 64° | 62° | — | 60° | — | — | 60–64° |
| 10d · 2026-09-13 | 68° | 70° | 67° | — | 57° | — | — | 57–70° |
| 9d · 2026-09-14 | 60° | 61° | 62° | 63° | 61° | — | — | 60–63° |
| 8d · 2026-09-15 | 63° | 68° | 65° | 63° | 61° | — | — | 61–68° |
| 7d · 2026-09-16 | 64° | 63° | 61° | 62° | 63° | — | — | 61–64° |
| 6d · 2026-09-17 | 64° | 55° | 62° | 62° | 59° | 63° | 64° | 55–64° |
| 5d · 2026-09-18 | 63° | 60° | 61° | 60° | 60° | 63° | 63° | 60–63° |
| 4d · 2026-09-19 | 63° | 59° | 60° | 61° | 58° | 64° | 64° | 58–64° |
| 3d · 2026-09-20 | 62° | 59° | 61° | 62° | 60° | 63° | 62° | 59–63° |
| 2d · 2026-09-21 | 62° | 59° | 62° | 64° | 60° | 62° | 63° | 59–64° |
| 1d · 2026-09-22 | 62° | 61° | 62° | 64° | 60° | 64° | 62° | 60–64° |
| actual | 64° |
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.