Was the forecast right for Boston on Sat Aug 29?
Boston, Massachusetts · daily high temperature in °F · forecasts from each model's archived runs, verified against the BOS observations
10 days out, 4 models put Boston's Sat Aug 29 high anywhere from 69° to 80°;by the final call, the day before, the field had settled to a median of 76°. The day verified at 74° against the BOS observations — partly cloudy.
GFS landed closest, off by 1.1°. UKMO ran 6° warm.
What every model said, at every lead
Daily-high calls for Sat Aug 29 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 |
|---|---|---|---|---|---|---|---|---|
| 10d · 2026-08-19 | 79° | 69° | 80° | — | 80° | — | — | 69–80° |
| 9d · 2026-08-20 | 73° | 83° | 79° | — | 75° | — | — | 73–83° |
| 8d · 2026-08-21 | 72° | 81° | 78° | 76° | 72° | — | — | 72–81° |
| 7d · 2026-08-22 | 76° | 76° | 82° | 78° | 84° | — | — | 76–84° |
| 6d · 2026-08-23 | 74° | 79° | 73° | 78° | 80° | 78° | 78° | 73–80° |
| 5d · 2026-08-24 | 75° | 76° | 78° | 73° | 72° | 74° | 74° | 72–78° |
| 4d · 2026-08-25 | 75° | 77° | 74° | 72° | 72° | 74° | 75° | 72–77° |
| 3d · 2026-08-26 | 77° | 77° | 78° | 80° | 72° | 76° | 80° | 72–80° |
| 2d · 2026-08-27 | 75° | 76° | 73° | 74° | 70° | 76° | 74° | 70–76° |
| 1d · 2026-08-28 | 75° | 76° | 78° | 76° | 73° | 76° | 80° | 73–80° |
| actual | 74° |
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.