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
14 days out, 4 models put Boston's Tue Sep 8 high anywhere from 69° to 79°;by the final call, the day before, the field had settled to a median of 78°. The day verified at 81° against the BOS observations — cloudy.
GEM landed closest, off by 0.7°. UKMO ran 5° cool.
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 | — | 81° | — | — | 76° | — | — | 76–81° |
| 14d · 2026-08-25 | 77° | 72° | 79° | — | 69° | — | — | 69–79° |
| 13d · 2026-08-26 | 76° | 86° | 79° | — | 73° | — | — | 73–86° |
| 12d · 2026-08-27 | 80° | 83° | 75° | — | 72° | — | — | 72–83° |
| 11d · 2026-08-28 | 71° | 74° | 79° | — | 70° | — | — | 70–79° |
| 10d · 2026-08-29 | 74° | 79° | 70° | — | 71° | — | — | 70–79° |
| 9d · 2026-08-30 | 79° | 73° | 81° | 73° | 69° | — | — | 69–81° |
| 8d · 2026-08-31 | 79° | 76° | 72° | 77° | 69° | — | — | 69–79° |
| 7d · 2026-09-01 | 79° | 80° | 82° | 75° | 83° | — | — | 75–83° |
| 6d · 2026-09-02 | 77° | 81° | 71° | 74° | 81° | 83° | 73° | 71–83° |
| 5d · 2026-09-03 | 74° | 79° | 78° | 73° | 73° | 82° | 76° | 73–82° |
| 4d · 2026-09-04 | 75° | 82° | 82° | 72° | 78° | 82° | 81° | 72–82° |
| 3d · 2026-09-05 | 78° | 79° | 80° | 81° | 78° | 80° | 81° | 78–81° |
| 2d · 2026-09-06 | 78° | 79° | 80° | 82° | 74° | 81° | 80° | 74–82° |
| 1d · 2026-09-07 | 78° | 79° | 80° | 82° | 77° | 78° | 76° | 76–82° |
| 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. 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.