Was the forecast right for Boston on Wed Sep 16?
Boston, Massachusetts · daily high temperature in °F · forecasts from each model's archived runs, verified against the BOS observations
13 days out, 4 models put Boston's Wed Sep 16 high anywhere from 66° to 78°; by the final call the field had settled to a median of 79°. The day verified at 80° against the BOS observations — cloudy.
UKMO landed closest, off by 1.1°. AIFS ran 6° cold.
What every model said, at every lead
Daily-high calls for Wed Sep 16 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 · 2026-09-01 | — | 75° | — | — | 70° | — | — | 70–75° |
| 14d · 2026-09-02 | 76° | 70° | — | — | 72° | — | — | 70–76° |
| 13d · 2026-09-03 | 73° | 74° | 66° | — | 78° | — | — | 66–78° |
| 12d · 2026-09-04 | 85° | 78° | 70° | — | 69° | — | — | 69–85° |
| 11d · 2026-09-05 | 75° | 87° | 76° | — | 73° | — | — | 73–87° |
| 10d · 2026-09-06 | 72° | 86° | 78° | — | 61° | — | — | 61–86° |
| 9d · 2026-09-07 | 81° | 79° | 76° | — | 61° | — | — | 61–81° |
| 8d · 2026-09-08 | 76° | 73° | 83° | 65° | 82° | — | — | 65–83° |
| 7d · 2026-09-09 | 78° | 80° | 75° | 79° | 77° | — | — | 75–80° |
| 6d · 2026-09-10 | 76° | 83° | 78° | 72° | 87° | 81° | — | 72–87° |
| 5d · 2026-09-11 | 75° | 81° | 78° | 76° | 72° | 86° | 83° | 72–86° |
| 4d · 2026-09-12 | 75° | 78° | 75° | 75° | 70° | 78° | 79° | 70–79° |
| 3d · 2026-09-13 | 76° | 79° | 76° | 73° | 75° | 79° | 80° | 73–80° |
| 2d · 2026-09-14 | 75° | 79° | 76° | 79° | 77° | 78° | 80° | 75–80° |
| 1d · 2026-09-15 | 74° | 79° | 74° | 82° | 77° | 75° | 81° | 74–82° |
| 0d · 2026-09-16 | 74° | 79° | 76° | 81° | 79° | 77° | 79° | 74–81° |
| actual | 80° |
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.