15-Day Weather Forecast - Belfast

15-day weather forecast for Belfast: temperatures from 8°C (46°F) to 20°C (68°F). Average daily high 16°C (61°F) over the next 15 days.

Hourly Forecast by Day

Today·11 Sep
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Temperature · peaks at +17°C

15-Day Temperature Trend

17°14°TodaySep20°13°Tmrw17°13°Sun19°15°Mon17°11°Tue16°12°Wed15°12°Thu15°11°Fri15°10°Sat15°10°Sun18°11°Mon16°10°Tue12°9°Wed12°8°Thu15°8°Fri
Colour scale for daily high temperature bars

15-Day Weather Forecast

Updated just now
  • Date
    High / Low
  • Fri, Sep 11Today
    +17°/+14°
    feels +15°0.1 mm · 4%17 km/hUV 3 · Low
    06:4819:50
  • Sat, Sep 12Tomorrow
    +20°/+13°
    feels +18°12.1 mm · 100%24 km/hUV 3 · Low
    06:5019:47
  • Sun, Sep 13Sun
    +17°/+13°
    feels +16°0 mm · 22%14 km/hUV 4 · Mod
    06:5219:45
  • Mon, Sep 14Mon
    +19°/+15°
    feels +19°1.5 mm · 76%22 km/hUV 3 · Mod
    06:5419:42
  • Tue, Sep 15Tue
    +17°/+11°
    feels +13°0 mm · 59%25 km/hUV 4 · Mod
    06:5619:40
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  • Wed, Sep 16Wed
    +16°/+12°
    feels +13°0.3 mm · 45%27 km/hUV 2 · Low
    06:5819:37
  • Thu, Sep 17Thu
    +15°/+12°
    feels +11°0 mm · 43%30 km/hUV 4 · Mod
    06:5919:35
  • Fri, Sep 18Fri
    +15°/+11°
    feels +10°0.4 mm · 45%27 km/hUV 2 · Low
    07:0119:32
  • Sat, Sep 19Sat
    +15°/+10°
    feels +11°0.8 mm · 41%25 km/hUV 3 · Low
    07:0319:30
  • Sun, Sep 20Sun
    +15°/+10°
    feels +12°0 mm · 38%21 km/hUV 4 · Mod
    07:0519:27
  • Mon, Sep 21Mon
    +18°/+11°
    feels +16°1.0 mm · 37%27 km/hUV 2 · Low
    07:0719:25
  • Tue, Sep 22Tue
    +16°/+10°
    feels +13°0.8 mm · 26%26 km/hUV 3 · Mod
    07:0919:22
  • Wed, Sep 23Wed
    +12°/+9°
    feels +8°1.2 mm · 39%21 km/hUV 3 · Low
    07:1019:20
  • Thu, Sep 24Thu
    +12°/+8°
    feels +7°0 mm · 29%20 km/hUV 1 · Low
    07:1219:17
  • Fri, Sep 25Fri
    +15°/+8°
    feels +15°1.2 mm · 39%8 km/hUV 2 · Low
    07:1419:15

Weather Insight

Belfast's 15-day outlook ranges from a low of 8°C to a high of 20°C, with an average daytime high near 16°C. Air quality is currently good (AQI 30), with no notable outdoor health concerns.

Today vs Normal

17°C+1° above normal

The long-term average high for today is 16°C.

12 of the last 19 days with published data ran above normal.

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

2026-08-19: 17°C17°2026-08-20: 16°C16°2026-08-21: 16°C16°2026-08-22: 16°C16°2026-08-23: 17°C17°2026-08-24: 18°C18°2026-08-25: 18°C18°2026-08-26: 19°C19°2026-08-27: 19°C19°2026-08-28: 19°C19°2026-08-29: 16°C16°2026-08-30: 17°C17°

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 Belfast

Over the next 15 days, Belfast is forecast to see temperatures ranging from 7°C to 20°C, averaging a daily high of 16°C. The extended outlook indicates frequent showers on 10 out of 15 days. Conditions are suitable for most outdoor activities; carry an umbrella on days with showers.