Weather risk planner
Weather risk for filming in London
Three exterior days in London in March: rain hits at least one with 80 % probability. In April it is 70 %. The tool is set to London — enter your own days.
- At least one day hit
- 80 %
- Expected lost days
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- Cover days to hold
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- Risk per day
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- Rain days in month
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- Sunshine per day
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- Daylight
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- Mean temperature
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Your shoot, played out 20 times
Same number of days in every month — click a month
- risk of at least one lost day
- sunshine hours per day
| Lost days | Probability | This many or fewer |
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Rain risk in London, month by month
London averages 13 rain days in March and 10 in April. A rain day here is any day with at least 1 mm of precipitation, averaged over 2015–2024. The risk columns assume every exterior day can be lost; the cover-day column is what you need to be 90 % sure a five-day exterior block finishes.
| Month | Rain days | 3 days: ≥ 1 hit | 5 days: ≥ 1 hit | Cover days (5 d, 90 %) | Sun/day | Mean temp |
|---|---|---|---|---|---|---|
| January | 12 | 77 % | 91 % | 3 | 4.3 h | 4.7 °C |
| February | 11 | 77 % | 92 % | 3 | 5.2 h | 5.9 °C |
| March | 13 | 80 % | 93 % | 4 | 6.5 h | 7.3 °C |
| April | 10 | 70 % | 87 % | 3 | 9.5 h | 9.3 °C |
| May | 11 | 73 % | 89 % | 3 | 10.6 h | 13.0 °C |
| June | 11 | 75 % | 90 % | 3 | 11.2 h | 16.4 °C |
| July | 11 | 73 % | 89 % | 3 | 11.2 h | 18.4 °C |
| August | 10 | 69 % | 86 % | 3 | 10.0 h | 18.0 °C |
| September | 11 | 75 % | 90 % | 3 | 8.4 h | 15.5 °C |
| October | 12 | 77 % | 91 % | 3 | 6.3 h | 12.1 °C |
| November | 12 | 78 % | 92 % | 3 | 4.4 h | 8.2 °C |
| December | 12 | 77 % | 91 % | 3 | 3.3 h | 6.8 °C |
When to shoot exteriors in London
Weighing daylight against rain days, June comes out best: 16 h 36 min of daylight, 11 rain days and 11.2 hours of sunshine a day. The sunniest month is June (11.2 h a day).
The rain risk barely moves through the year in London: five exterior days run a 86 % to 93 % risk of losing at least one day, whatever the month. Choosing the month buys you little here; cover days and a flexible schedule buy you more.
Rain days are not grey days: even in March, the wettest month, the sun shines 6.5 hours a day on average. Many of those rain days are wet for an hour, not all day — if your scenes can wait out a shower, lower the share slider in the tool.
Frequently asked
What is the rainiest month in London?
March, with 13 days of at least 1 mm rain on average (2015–2024). The driest is April with 10.
How many cover days should I plan for an exterior shoot in London?
For five exterior days and 90 % certainty: 3 in April, 4 in March. The tool above calculates it for your exact number of days.
Is this a weather forecast?
No — it is climate: what the last ten years looked like on average. From about ten days before the shoot, the national weather service forecast is the better source.