Was the forecast right for Boston on Thu Jul 30?
Boston, Massachusetts · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
3 days out, 7 models put Boston's Thu Jul 30 high anywhere from 19° to 23°; by the final call the field had settled to a median of 20°. The day verified at 23° against the ECMWF IFS analysis, with 13.2 mm of precipitation — rain.
GEM landed closest, off by 1.4°. AIGFS ran 4° cold.
What every model said, at every lead
Daily-high calls for Thu Jul 30 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 |
|---|---|---|---|---|---|---|---|---|
| 3d · 2026-07-27 | 21° | 21° | 23° | 20° | 20° | 19° | 20° | 19–23° |
| 2d · 2026-07-28 | 20° | 19° | 23° | 20° | 20° | 20° | 19° | 19–23° |
| 1d · 2026-07-29 | 20° | 19° | 20° | 19° | 20° | 20° | 20° | 19–20° |
| 0d · 2026-07-30 | 20° | 19° | 21° | 22° | 20° | 20° | 20° | 19–22° |
| actual | 23° |
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 ECMWF IFS analysis (temperature_2m_max). Archive depth varies by city; receipts exist only for dates the archive watched arrive.