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Nerd mode: every forecast, readouts, filters and range & bearing for weather enthusiasts

This week’s weatherBelfast, United Kingdom

Rain is likely in Belfast on Tuesday

Nearly all of NOAA’s 31 GEFS forecasts bring measurable rain to Belfast Tue 7 p.m.–1 a.m. BST; 7 in 10 bring 2.5 mm or more.

NOAA GEFS, 31 forecasts · Mon 28 Sep 18Z run · updated Tues., Sept. 29, 12:03 a.m. BST · times are Belfast’s (BST)

See it on the globe For warnings, follow your national weather service.

Quick answers

Will it rain in Belfast this week?
The best chances of measurable rain: Tuesday (nearly all forecasts, 7 p.m.–1 a.m.); Wednesday (nearly all forecasts, 1–7 a.m.); Thursday (5 in 10 forecasts, 7 p.m.–1 a.m.); Friday (8 in 10 forecasts, 1–7 p.m.). Drier: Sat (fewer than 2 in 10 forecasts in any six hours). Times are BST.
How much rain will Belfast get this week?
By Mon., Oct. 5, 7 p.m. BST (the end of the forecast), the middle forecast has 21 mm of rain and melted snow, counting from Tue 1 a.m. 8 in 10 forecasts bring 13 mm or more in total; 3 in 10 forecasts bring 25 mm or more.
How windy will it get in Belfast?
Gusts over 64 km/h: 9 in 10 forecasts at Tue 7 p.m. BST. The middle forecast’s strongest gust is 68 km/h, Tue 7 p.m. Checked every six hours, so a brief peak can fall between.
How warm or cold will it be in Belfast?
At the six-hourly times, the middle forecast runs from 7°C (Sat 7 a.m.) to 17°C (Tue 7 p.m.) BST. The day’s real high and low can fall between those times.
Are any storms heading for Belfast?
No storm Stormlines tracks has 1 in 10 forecasts passing its centre within 160 kilometres of Belfast this week.

Chance of rain, six hours at a time

Tue 1–7 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneTue 7 a.m.–1 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneTue 1–7 p.m.: 9 in 10 forecasts with measurable rain; middle forecast 0.9 mmTue 7 p.m.–1 a.m.: nearly all forecasts with measurable rain; middle forecast 3.7 mmWed 1–7 a.m.: nearly all forecasts with measurable rain; middle forecast 7.0 mmWed 7 a.m.–1 p.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.3 mmWed 1–7 p.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.4 mmWed 7 p.m.–1 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 1–7 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 7 a.m.–1 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 1–7 p.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneThu 7 p.m.–1 a.m.: 5 in 10 forecasts with measurable rain; middle forecast 0.3 mmFri 1–7 a.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.4 mmFri 7 a.m.–1 p.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.4 mmFri 1–7 p.m.: 8 in 10 forecasts with measurable rain; middle forecast 0.6 mmFri 7 p.m.–1 a.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneSat 1–7 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 7 a.m.–1 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 1–7 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 7 p.m.–1 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSun 1–7 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSun 7 a.m.–1 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneSun 1–7 p.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneSun 7 p.m.–1 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneMon 1–7 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneMon 7 a.m.–1 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneMon 1–7 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost none

Each bar is the share of the 31 forecasts with measurable rain or melted snow in that six hours; the darker the bar, the more forecasts agree. Local days, BST.

The week, day by day

DayChance of rain2.5 mm or moreTotal by day’s endStrongest gustTemperature
Tue 29nearly all7 in 104.8 mm · <1 in 1068 km/h · 9 in 10 >64 km/h11°C–17°C
Wed 30nearly all9 in 1014 mm · 7 in 1063 km/h · 4 in 10 >64 km/h13°C–16°C
Thu 15 in 101 in 1015 mm · 7 in 1045 km/h8°C–14°C
Fri 28 in 102 in 1020 mm · 8 in 1045 km/h12°C–14°C
Sat 31 in 10<1 in 1021 mm · 8 in 1016 km/h7°C–14°C
Sun 42 in 101 in 1021 mm · 8 in 1026 km/h10°C–15°C
Mon 5 (part)1 in 10<1 in 1021 mm · 8 in 1025 km/h10°C–15°C

Chances are the highest in any six hours of the day. “Total by day’s end” is the middle forecast’s running total since Tue 1 a.m., and the share of forecasts with 13 mm or more by then; totals aren’t added up day by day, because the middle forecast of each day isn’t the same forecast. Gusts and temperatures are read every six hours.

Storms near Belfast

No storm Stormlines tracks has 1 in 10 forecasts passing its centre near Belfast this week. Every storm we’re tracking →

About these numbers

They come from one source, NOAA’s Global Ensemble Forecast System (GEFS): 31 runs of the same model, each started slightly differently, read at Belfast’s coordinates on a grid about 55 km (35 miles) apart. “8 in 10 forecasts” means 8 in 10 of those runs. Nothing is adjusted for local effects such as coasts, lakes, hills or city heat, so the numbers can differ from your local official forecast, especially for snow and showers.

“Measurable rain” counts rain or melted snow in a six-hour period. Not an official forecast: follow your national weather service for warnings and decisions. How the forecasts are read: how to read the maps and the glossary.

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