Weather risk for filming in Rennes
Rennes averages 14 rain days in March — a three-day exterior shoot then hits at least one with 85 % probability. In July (9 rain days) the same risk drops to 66 %. The calculator above is preset to Rennes and runs the numbers for your count of exterior days.
Weather risk calculator for Rennes
- Risk per day
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- At least one day hit
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- Expected lost days
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Rain risk in Rennes by month
The "risk (3 days)" column answers the question behind every weather contingency: how likely does a three-day exterior block lose at least one day? From roughly 60 % upward, a cover set stops being optional and belongs in the budget.
| Month | Rain days | Mean temp | Sun hours/day | Risk (3 days) |
|---|---|---|---|---|
| January | 13 | 5.9 °C | 4.3 | 82 % |
| February | 11 | 6.8 °C | 5.7 | 75 % |
| March | 14 | 8.5 °C | 7.4 | 85 % |
| April | 11 | 10.9 °C | 10.0 | 75 % |
| May | 12 | 14.0 °C | 10.7 | 78 % |
| June | 11 | 17.5 °C | 11.5 | 75 % |
| July | 9 | 19.2 °C | 11.7 | 66 % |
| August | 9 | 19.0 °C | 10.8 | 66 % |
| September | 10 | 16.6 °C | 9.3 | 70 % |
| October | 11 | 13.3 °C | 7.0 | 75 % |
| November | 13 | 9.3 °C | 5.4 | 82 % |
| December | 13 | 7.5 °C | 4.3 | 82 % |
The best month for exteriors
Combining daylight and rain days, July comes out ahead in Rennes: 15h 41min of usable light against 9 mean rain days. The driest month (July) and the brightest are not automatically the same — which is exactly why the combined view matters.
For scheduling, a weather day costs more than the day itself: location availability, crew follow-on bookings and possibly the travel home. TillyGen puts the month's rain risk right next to the sun window inside the schedule — together they decide which day can happen outside.
Frequently asked
When does it rain least in Rennes?
July, with a mean of 9 rain days. The most falls in March with 14.
How is the washout risk computed?
Rain days ÷ 30 gives the per-day hit probability; across N exterior days, 1 − (1 − p)ᴺ is the chance of at least one hit. Deliberately simple and conservative — it prices the month's structural risk rather than forecasting weather.
What is the best month to shoot in Rennes?
On light and rain combined, July. The matching sun times live on the golden-hour page for Rennes and on the city page.