Was the forecast right for Boston on Sun Oct 18?
Boston, Massachusetts · daily high temperature in °C · forecasts from each model's archived runs, verified against the BOS observations
14 days out, 4 models put Boston's Sun Oct 18 high anywhere from 16° to 19°;by the final call, the day before, the field had settled to a median of 12°. The day verified at 12° against the BOS observations — clear.
GEM landed closest, off by 0.2°. ICON ran 1° warm.
What every model said, at every lead
Daily-high calls for Sun Oct 18 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 · 2026-10-03 | — | 19° | — | — | 14° | — | — | 14–19° |
| 14d · 2026-10-04 | 19° | 18° | 16° | — | 16° | — | — | 16–19° |
| 13d · 2026-10-05 | 14° | 14° | 23° | — | 12° | — | — | 12–23° |
| 12d · 2026-10-06 | 11° | 15° | 12° | — | 16° | — | — | 11–16° |
| 11d · 2026-10-07 | 14° | 12° | 13° | — | 23° | — | — | 12–23° |
| 10d · 2026-10-08 | 9° | 14° | 18° | — | 12° | — | — | 9–18° |
| 9d · 2026-10-09 | 8° | 8° | 11° | 8° | 13° | — | — | 8–13° |
| 8d · 2026-10-10 | 10° | 8° | 9° | 7° | 9° | — | — | 7–10° |
| 7d · 2026-10-11 | 15° | 8° | 13° | 11° | 11° | — | — | 8–15° |
| 6d · 2026-10-12 | — | 8° | 13° | 10° | 11° | 8° | 8° | 8–13° |
| 5d · 2026-10-13 | 10° | 16° | 13° | 12° | 15° | 15° | 13° | 10–16° |
| 4d · 2026-10-14 | 13° | 16° | 9° | 13° | 15° | 12° | 11° | 9–16° |
| 3d · 2026-10-15 | 12° | 15° | 12° | 10° | 10° | 12° | 13° | 10–15° |
| 2d · 2026-10-16 | 12° | 13° | 11° | 10° | 10° | 13° | 12° | 10–13° |
| 1d · 2026-10-17 | 12° | 13° | 11° | 12° | 11° | 13° | 11° | 11–13° |
| actual | 12° |
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.