Was the forecast right for Boston on Sat Sep 26?
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 Sat Sep 26 high anywhere from 64° to 72°;by the final call, the day before, the field had settled to a median of 60°. The day verified at 61° against the BOS observations, with 1.02 in of precipitation — thunderstorms.
ICON landed closest, off by 0.5°. GFS ran 3° cool.
What every model said, at every lead
Daily-high calls for Sat Sep 26 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 · 2026-09-11 | — | 73° | — | — | 68° | — | — | 68–73° |
| 14d · 2026-09-12 | 69° | 70° | 72° | — | 64° | — | — | 64–72° |
| 13d · 2026-09-13 | 72° | 68° | 70° | — | 67° | — | — | 67–72° |
| 12d · 2026-09-14 | 70° | 73° | 72° | — | 62° | — | — | 62–73° |
| 11d · 2026-09-15 | 66° | 77° | 64° | — | 77° | — | — | 64–77° |
| 10d · 2026-09-16 | 66° | 75° | 68° | — | 61° | — | — | 61–75° |
| 9d · 2026-09-17 | 60° | 70° | 59° | 65° | 60° | — | — | 59–70° |
| 8d · 2026-09-18 | 62° | 56° | 60° | 58° | 62° | — | — | 56–62° |
| 7d · 2026-09-19 | 61° | 62° | 62° | 57° | 57° | — | — | 57–62° |
| 6d · 2026-09-20 | 58° | 64° | 60° | 68° | 59° | 62° | 64° | 58–68° |
| 5d · 2026-09-21 | 60° | 55° | 62° | 56° | 68° | 67° | 64° | 55–68° |
| 4d · 2026-09-22 | 59° | 56° | 62° | 57° | 57° | 57° | 66° | 56–66° |
| 3d · 2026-09-23 | 60° | 63° | 63° | 61° | 56° | 60° | 64° | 56–64° |
| 2d · 2026-09-24 | 62° | 57° | 60° | 57° | 57° | 61° | 68° | 57–68° |
| 1d · 2026-09-25 | 60° | 59° | 60° | 60° | 58° | 60° | 63° | 58–63° |
| actual | 61° |
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.