Was the forecast right for Boston on Tue Sep 8?
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 Tue Sep 8 high anywhere from 74° to 88°; by the final call the field had settled to a median of 79°. The day verified at 81° against the BOS observations — cloudy.
ICON landed closest, off by 0.8°. GFS ran 4° cold.
What every model said, at every lead
Daily-high calls for Tue Sep 8 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 · 2026-08-24 | — | 78° | — | — | 88° | — | — | 78–88° |
| 14d · 2026-08-25 | 80° | 75° | — | — | 88° | — | — | 75–88° |
| 13d · 2026-08-26 | 77° | 88° | 88° | — | 74° | — | — | 74–88° |
| 12d · 2026-08-27 | 74° | 98° | 85° | — | 72° | — | — | 72–98° |
| 11d · 2026-08-28 | 78° | 95° | 76° | — | 81° | — | — | 76–95° |
| 10d · 2026-08-29 | 78° | 71° | 73° | — | 83° | — | — | 71–83° |
| 9d · 2026-08-30 | 79° | 70° | 69° | — | 70° | — | — | 69–79° |
| 8d · 2026-08-31 | 78° | 79° | 75° | 73° | 79° | — | — | 73–79° |
| 7d · 2026-09-01 | 78° | 80° | 68° | 76° | 69° | — | — | 68–80° |
| 6d · 2026-09-02 | 75° | 81° | 82° | 74° | 80° | 81° | — | 74–82° |
| 5d · 2026-09-03 | 74° | 81° | 81° | 75° | 67° | 84° | 76° | 67–84° |
| 4d · 2026-09-04 | 78° | 81° | 80° | 74° | 76° | 83° | 81° | 74–83° |
| 3d · 2026-09-05 | 77° | 79° | 80° | 77° | 74° | 77° | 81° | 74–81° |
| 2d · 2026-09-06 | 78° | 80° | 82° | 82° | 79° | 80° | 81° | 78–82° |
| 1d · 2026-09-07 | 77° | 78° | 80° | 82° | 74° | 80° | 79° | 74–82° |
| 0d · 2026-09-08 | 77° | 79° | 79° | 82° | 77° | 80° | 77° | 77–82° |
| actual | 81° |
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.