15-Day Weather Forecast - St. John's

15-day weather forecast for St. John's: temperatures from 7°C (45°F) to 18°C (64°F). Average daily high 15°C (59°F) over the next 15 days.

Hourly Forecast by Day

Today·11 Sep
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Temperature · peaks at +18°C

15-Day Temperature Trend

18°13°TodaySep13°8°Tmrw18°8°Sun17°13°Mon18°11°Tue14°11°Wed18°13°Thu18°12°Fri13°9°Sat12°8°Sun14°10°Mon18°11°Tue14°10°Wed13°8°Thu13°7°Fri
Colour scale for daily high temperature bars

15-Day Weather Forecast

Updated just now
  • Date
    High / Low
  • Fri, Sep 11Today
    +18°/+13°
    feels +15°3.1 mm · 100%32 km/hUV 6 · Mod
    06:3219:20
  • Sat, Sep 12Tomorrow
    +13°/+8°
    feels +10°0.8 mm · 33%27 km/hUV 5 · Mod
    06:3419:18
  • Sun, Sep 13Sun
    +18°/+8°
    feels +16°22 km/hUV 5 · Mod
    06:3519:16
  • Mon, Sep 14Mon
    +17°/+13°
    feels +15°11.1 mm · 79%38 km/hUV 4 · Mod
    06:3619:14
  • Tue, Sep 15Tue
    +18°/+11°
    feels +18°9.4 mm · 79%30 km/hUV 2 · Low
    06:3819:12
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  • Wed, Sep 16Wed
    +14°/+11°
    feels +14°0 mm · 24%12 km/hUV 5 · Mod
    06:3919:10
  • Thu, Sep 17Thu
    +18°/+13°
    feels +19°0 mm · 19%8 km/hUV 5 · Mod
    06:4019:08
  • Fri, Sep 18Fri
    +18°/+12°
    feels +18°0 mm · 26%10 km/hUV 5 · Mod
    06:4219:06
  • Sat, Sep 19Sat
    +13°/+9°
    feels +13°0 mm · 24%20 km/hUV 1 · Low
    06:4319:04
  • Sun, Sep 20Sun
    +12°/+8°
    feels +10°0 mm · 27%12 km/hUV 3 · Mod
    06:4419:02
  • Mon, Sep 21Mon
    +14°/+10°
    feels +10°3.2 mm · 54%33 km/hUV 5 · Mod
    06:4619:00
  • Tue, Sep 22Tue
    +18°/+11°
    feels +15°10.6 mm · 46%32 km/hUV 4 · Mod
    06:4718:58
  • Wed, Sep 23Wed
    +14°/+10°
    feels +10°0 mm · 31%25 km/hUV 1 · Low
    06:4818:56
  • Thu, Sep 24Thu
    +13°/+8°
    feels +9°0 mm · 25%17 km/hUV 1 · Low
    06:5018:54
  • Fri, Sep 25Fri
    +13°/+7°
    feels +10°0 mm · 16%27 km/hUV 5 · Mod
    06:5118:52

Weather Insight

St. John's's 15-day outlook ranges from a low of 7°C to a high of 18°C, with an average daytime high near 15°C. Air quality is currently good (AQI 39), with no notable outdoor health concerns.

Today vs Normal

18°C+3° above normal

The long-term average high for today is 15°C.

16 of the last 28 days with published data ran above normal.

It continues that pattern - today's forecast is also running above normal.

2026-08-28: 21°C21°2026-08-29: 18°C18°2026-08-30: 19°C19°2026-08-31: 18°C18°2026-09-01: 15°C15°2026-09-02: 14°C14°2026-09-03: 16°C16°2026-09-04: 17°C17°2026-09-05: 15°C15°2026-09-06: 16°C16°2026-09-07: 17°C17°2026-09-08: 16°C16°

Red = above normal, blue = at or below · last 12 days

Air Quality

Air Quality
Good

Air quality is considered satisfactory, and air pollution poses little or no risk. It’s a good day to be active outside.

Extended Outlook for St. John's

Over the next 15 days, St. John's is forecast to see temperatures ranging from 6°C to 19°C, averaging a daily high of 15°C. The extended outlook indicates significant rainfall totalling 38.2 mm spread across 6 days. Conditions are suitable for most outdoor activities; carry an umbrella on days with showers.