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Saint John weekend weather

This weekend in Saint John, New Brunswick, 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 22° across the weekend. Agreement is low — the weekend is genuinely up in the air at this range.

Sat

2026-08-01 — every model, side by side
Env. CanadaGEM model
20°
Cloudy
High 20°·Low 15°·Rain 14%
EuropeanECMWF
22°
Drizzle
High 22°·Low 16°·Rain 16%
AmericanNOAA GFS
26°
Cloudy
High 26°·Low 14°·Rain 4%

The models are 6° apart on this day. That is genuine uncertainty — any app showing you a single confident number is hiding it.

Sun

2026-08-02 — every model, side by side
Env. CanadaGEM model
19°
Light drizzle
High 19°·Low 15°·Rain 14%
EuropeanECMWF
20°
Cloudy
High 20°·Low 14°·Rain 10%
AmericanNOAA GFS
23°
Fog
High 23°·Low 14°·Rain 36%

The models range from 19° to 23°. Treat the middle of that range as the likely outcome and keep a backup plan.

Where the models disagree

temperature and rain, judged separately
DayTemperatureRain
Today±3°19° to 21°±22%51% to 73% chance
Tomorrow±1°20° to 20°±68%18% to 86% chance
Sat±6°20° to 26°±12%4% to 16% chance
Sun±4°19° to 23°±26%10% to 36% chance
Mon±6°18° to 24°±13%58% to 71% 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?
The models are not currently showing a high weekend rain risk, and they broadly agree with each other.
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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