15-Day Weather Forecast - Belfast

15-day weather forecast for Belfast: temperatures from 8°C (46°F) to 19°C (66°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 +18°C

15-Day Temperature Trend

18°14°TodaySep19°13°Tmrw18°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
    +18°/+14°
    feels +15°0.1 mm · 4%17 km/hUV 3 · Low
    06:4819:50
  • Sat, Sep 12Tomorrow
    +19°/+13°
    feels +19°9.9 mm · 100%23 km/hUV 3 · Low
    06:5019:47
  • Sun, Sep 13Sun
    +18°/+13°
    feels +17°0 mm · 8%15 km/hUV 3 · Low
    06:5219:45
  • Mon, Sep 14Mon
    +19°/+15°
    feels +19°1.5 mm · 83%22 km/hUV 3 · Mod
    06:5419:42
  • Tue, Sep 15Tue
    +17°/+11°
    feels +13°0 mm · 62%25 km/hUV 4 · Mod
    06:5619:40
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  • Wed, Sep 16Wed
    +16°/+12°
    feels +13°0.3 mm · 40%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 19°C, with an average daytime high near 16°C. Air quality is currently Moderate (AQI 52), driven mainly by PM2.5 at 9.6 μg/m³.

Today vs Normal

18°C+2° 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
Moderate

Air quality is acceptable for most people. Unusually sensitive individuals should consider reducing prolonged or heavy outdoor exertion.

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.