Weather risk for filming in Galway
Galway averages 19 rain days in August — a three-day exterior shoot then hits at least one with 95 % probability. In April (13 rain days) the same risk drops to 82 %. The calculator above is preset to Galway and runs the numbers for your count of exterior days.
Weather risk calculator for Galway
- Risk per day
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- At least one day hit
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- Expected lost days
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Runs entirely in your browser — no sign-up, nothing transmitted.
Rain risk in Galway 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 | 16 | 6.3 °C | 3.6 | 90 % |
| February | 17 | 6.7 °C | 4.8 | 92 % |
| March | 16 | 7.2 °C | 6.3 | 90 % |
| April | 13 | 9.1 °C | 8.5 | 82 % |
| May | 15 | 12.0 °C | 10.2 | 88 % |
| June | 16 | 14.3 °C | 9.7 | 90 % |
| July | 17 | 15.4 °C | 9.0 | 92 % |
| August | 19 | 15.3 °C | 8.6 | 95 % |
| September | 16 | 13.8 °C | 6.8 | 90 % |
| October | 18 | 11.3 °C | 5.4 | 94 % |
| November | 16 | 8.5 °C | 3.9 | 90 % |
| December | 19 | 7.3 °C | 3.0 | 95 % |
The best month for exteriors
Combining daylight and rain days, June comes out ahead in Galway: 16h 57min of usable light against 16 mean rain days. The driest month (April) 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 Galway?
April, with a mean of 13 rain days. The most falls in August with 19.
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 Galway?
On light and rain combined, June. The matching sun times live on the golden-hour page for Galway and on the city page.