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London weekend weather

This weekend in London, Ontario, model by model. Weekend forecasts are far enough out that the models often split - so we show you where.

Weekend

The models centre on about 20° across the weekend. Agreement is low - the weekend is genuinely up in the air at this range. Rain chance reaches 91% on at least one model.

Today

2026-09-19 — every model, side by side
Env. CanadaGEM model
20°
Drizzle
High 20°·Low 14°·Rain 33%
EuropeanECMWF
18°
Light rain
High 18°·Low 13°·Rain 84%
AmericanNOAA GFS
19°
Cloudy
High 19°·Low 13°·Rain 30%

The models range from 18° to 20°. Treat the middle of that range as the likely outcome and keep a backup plan.

Tomorrow

2026-09-20 — every model, side by side
Env. CanadaGEM model
21°
Rain
High 21°·Low 13°·Rain 48%
EuropeanECMWF
21°
Heavy drizzle
High 21°·Low 13°·Rain 91%
AmericanNOAA GFS
21°
Cloudy
High 21°·Low 11°·Rain 52%

All 3 models land within under a degree of each other for this day — that is a forecast you can plan on.

Where the models disagree

temperature and rain, judged separately
DayTemperatureRain
Today±3°18° to 20°±54%30% to 84% chance
Tomorrowmodels agree21° to 21°±43%48% to 91% chance
Mon±4°15° to 19°±5%0% to 5% chance
Tue±4°16° to 20°±1%9% to 10% chance
Wed±3°14° to 17°±10%19% to 29% chance

The models often agree on temperature and still split on rain, and rain is usually what decides whether a plan survives. A wide rain range means the shower is genuinely uncertain, not that the forecast is wrong.

Common questions

Will it rain this weekend?
At least one model puts the weekend rain chance as high as 91%. Weekend forecasts sit far enough ahead that models frequently disagree on showers - when they do, no single app can honestly tell you it will or will not rain.
How reliable is a weekend forecast?
It depends how far away the weekend is. Forecast error grows steadily with lead time, so a Saturday forecast made on Friday is far stronger than one made the previous Monday. The honest signal is model agreement: when they converge the forecast is solid, and when they spread the weekend is genuinely uncertain.

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