Was the forecast right for Boston on Mon Sep 28?
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 Mon Sep 28 high anywhere from 65° to 77°;by the final call, the day before, the field had settled to a median of 60°. The day verified at 58° against the BOS observations, with 1.0 in of precipitation — showers.
GFS landed closest, off by 0.3°. ICON ran 4° warm.
What every model said, at every lead
Daily-high calls for Mon Sep 28 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 · 2026-09-13 | — | 59° | — | — | 61° | — | — | 59–61° |
| 14d · 2026-09-14 | 65° | 69° | 77° | — | 66° | — | — | 65–77° |
| 13d · 2026-09-15 | 68° | 74° | 68° | — | 61° | — | — | 61–74° |
| 12d · 2026-09-16 | 59° | 66° | 63° | — | 71° | — | — | 59–71° |
| 11d · 2026-09-17 | 60° | 70° | 67° | — | 61° | — | — | 60–70° |
| 10d · 2026-09-18 | 62° | 70° | 68° | — | 70° | — | — | 62–70° |
| 9d · 2026-09-19 | 61° | 73° | 71° | 63° | 58° | — | — | 58–73° |
| 8d · 2026-09-20 | 67° | 68° | 59° | 65° | 59° | — | — | 59–68° |
| 7d · 2026-09-21 | 62° | 65° | 60° | 61° | 63° | — | — | 60–65° |
| 6d · 2026-09-22 | 63° | 60° | 61° | 60° | 57° | 63° | — | 57–63° |
| 5d · 2026-09-23 | 60° | 57° | 62° | 60° | 56° | 62° | 60° | 56–62° |
| 4d · 2026-09-24 | 63° | 59° | 59° | 59° | 57° | 61° | 61° | 57–63° |
| 3d · 2026-09-25 | 61° | 59° | 71° | 61° | 60° | 60° | 62° | 59–71° |
| 2d · 2026-09-26 | 60° | 60° | 60° | 59° | 59° | 60° | 61° | 59–61° |
| 1d · 2026-09-27 | 60° | 58° | 60° | 59° | 58° | 62° | 61° | 58–62° |
| actual | 58° |
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.