Was the forecast right for Boston on Sat Sep 19?
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 Sat Sep 19 high anywhere from 60° to 76°; by the final call the field had settled to a median of 64°. The day verified at 62° against the BOS observations — cloudy.
ECMWF landed closest, off by 0.6°. UKMO ran 3° warm.
What every model said, at every lead
Daily-high calls for Sat Sep 19 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 · 2026-09-04 | — | 82° | — | — | 66° | — | — | 66–82° |
| 14d · 2026-09-05 | 71° | 67° | — | — | 70° | — | — | 67–71° |
| 13d · 2026-09-06 | 69° | 68° | 76° | — | 60° | — | — | 60–76° |
| 12d · 2026-09-07 | 65° | 71° | 71° | — | 63° | — | — | 63–71° |
| 11d · 2026-09-08 | 68° | 79° | 66° | — | 63° | — | — | 63–79° |
| 10d · 2026-09-09 | 63° | 89° | 68° | — | 79° | — | — | 63–89° |
| 9d · 2026-09-10 | 68° | 70° | 63° | — | 70° | — | — | 63–70° |
| 8d · 2026-09-11 | 74° | 69° | 76° | 74° | 79° | — | — | 69–79° |
| 7d · 2026-09-12 | 72° | 65° | 69° | 68° | 70° | — | — | 65–72° |
| 6d · 2026-09-13 | 64° | 72° | 65° | 68° | 68° | 77° | — | 64–77° |
| 5d · 2026-09-14 | 64° | 68° | 68° | 66° | 66° | 67° | 68° | 64–68° |
| 4d · 2026-09-15 | 64° | 66° | 63° | 62° | 60° | 65° | 64° | 60–66° |
| 3d · 2026-09-16 | 64° | 65° | 62° | 64° | 60° | 63° | 65° | 60–65° |
| 2d · 2026-09-17 | 64° | 65° | 62° | 63° | 62° | 63° | 65° | 62–65° |
| 1d · 2026-09-18 | 64° | 65° | 63° | 63° | 62° | 63° | 64° | 62–65° |
| 0d · 2026-09-19 | 64° | 64° | 63° | 64° | 64° | 63° | 65° | 63–65° |
| actual | 62° |
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.