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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Toronto Post Weather Desk. Data from Environment and Climate Change Canada and other national met services via Open-Meteo.
Saint John New Brunswick faces a humid continental climate heavily moderated by the Bay of Fundy, giving mild summers and cold, snowy winters. The live forecast above shows today’s conditions near the seasonal norm with moderate winds and a chance of patchy fog.
What is the typical temperature range for Saint John?
Daytime highs in January average –2°C, while July highs reach 22°C. The maritime influence keeps winters less severe than inland areas, but frequent cloud and fog keep summer warmth moderate. Overnight lows in winter drop to around –12°C; in summer they hover near 11°C.
How does the Bay of Fundy affect Saint John weather?
The Bay of Fundy’s cold waters produce dense fog, especially in late spring and early summer. This fog bank often lingers along the coast, mixing with onshore breezes to reduce visibility and create a damp chill. The tidal flow also influences local wind patterns, adding variability to the daily forecast.
When is the foggiest time of year in Saint John?
Fog peaks from May to July as warm land air meets the cold Bay of Fundy waters. Dense sea fog often reduces visibility below 1 km during morning and evening hours.
Does Saint John get extreme winter storms?
Yes – nor’easters and low-pressure systems from the Atlantic can bring heavy snow and strong winds, occasionally causing closures. Blowing snow and freezing rain are also common in mid-winter.
Is summer in Saint John humid?
Moderately humid. Dew points sit in the mid-teens, and afternoon sea breezes keep conditions comfortable. Only a few days each July hit humidex values above 30.
Sources
For broader conditions across the country, visit our Canada weather hub. Compare Saint John’s coastal climate with Vancouver weather to see how maritime influences differ on each coast.