Was the forecast right for Boston on Mon Aug 24?

Boston, Massachusetts · daily high temperature in °F · forecasts from each model's archived runs, verified against the BOS observations

4 days out, 7 models put Boston's Mon Aug 24 high anywhere from 78° to 85°; by the final call the field had settled to a median of 82°. The day verified at 85° against the BOS observations — cloudy.

GEM landed closest, off by 0.8°. AIFS ran 5° cold.

4 days out the models said 78–85; it hit 85. GEM led (off 0.8°F); AIFS ran 5°F cold. — The shareable card for this receipt — what this page looks like pasted into a thread.

What every model said, at every lead

Daily-high calls for Mon Aug 24 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
4d · 2026-08-20	78°	80°	83°	78°	78°	85°	79°	78–85°
3d · 2026-08-21	78°	81°	81°	77°	81°	82°	83°	77–83°
2d · 2026-08-22	78°	81°	80°	79°	81°	82°	85°	78–85°
1d · 2026-08-23	79°	81°	79°	85°	82°	82°	82°	79–85°
0d · 2026-08-24	80°	82°	80°	84°	82°	82°	82°	80–84°
actual								85°

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.