The Spread

How the forecast changed in 24 hours

Shows how the forecast for the selected date at 18Z changed over the last 24 hours of model runs.

Valid 18Z 31 Aug · GFS 12Z 29 Aug → 12Z 30 Aug

Colder °C warmer · range -7.8 to +9.0 °C

Every map on this page is drawn from model output we store ourselves, not from anyone's picture of it. The per-city read of the same day — which cities the models are fighting about, and what the discussion makes of it — is on the national page.