Climate averages 1991–2020
Galway weather
in September.
A mild, moderately wet month: the 4th warmest and the driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Galway: daytime highs average 16.2°C and nights cool to about 10.8°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 75 mm of rain on roughly 12 days, which makes September a moderately wet month (the driest month of the year). Daylight, from sunrise to sunset, lasts about 12 h 45 min on an average September day.
The nearest other city in this atlas is Limerick (73 km away). In September its highs average 16.5°C, about as warm as Galway, with 76 mm of rain.
Among the 5 cities listed in Ireland, Galway ranks 4th of 5 for the warmest September highs and 4th of 5 for the driest September (rainfall, lowest first). The mean September high of those 5 cities is 16.4°C; Galway is 0.2°C cooler than that mean.
From September to October, average highs fall by 3.1°C to 13.1°C, and monthly rainfall rises from 75 mm to 95 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Galway climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 8.0°C3.8°C | 3.8°C | 99 | 15.4 | 8.18 h |
| February | 8.5°C3.5°C | 3.5°C | 85 | 13.0 | 9.810 h |
| March | 9.9°C4.1°C | 4.1°C | 78 | 13.3 | 11.812 h |
| April | 12.2°C5.5°C | 5.5°C | 76 | 13.7 | 13.914 h |
| May | 14.8°C8.2°C | 8.2°C | 79 | 13.5 | 15.816 h |
| June | 16.9°C10.6°C | 10.6°C | 79 | 12.9 | 16.917 h |
| July | 18.0°C12.3°C | 12.3°C | 83 | 14.5 | 16.416 h |
| August | 17.8°C12.2°C | 12.2°C | 91 | 14.0 | 14.815 h |
| September, selected | 16.2°C10.8°C | 10.8°C | 75 | 12.3 | 12.713 h |
| October | 13.1°C8.3°C | 8.3°C | 95 | 14.0 | 10.611 h |
| November | 10.2°C5.8°C | 5.8°C | 101 | 14.3 | 8.79 h |
| December | 8.3°C4.1°C | 4.1°C | 104 | 15.2 | 7.68 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Limerick in SeptemberIreland · 73 kmHigh 16.5°C · Low 10.8°C · 76 mm rain
- Cork in SeptemberIreland · 158 kmHigh 16.7°C · Low 11.7°C · 64 mm rain
- Tallaght in SeptemberIreland · 178 kmHigh 16.1°C · Low 10.5°C · 70 mm rain
- Dublin in SeptemberIreland · 186 kmHigh 16.5°C · Low 11.0°C · 70 mm rain
- Derry in SeptemberUnited Kingdom · 223 kmHigh 15.4°C · Low 10.4°C · 75 mm rain
- Lisburn in SeptemberUnited Kingdom · 242 kmHigh 15.6°C · Low 10.6°C · 70 mm rain
- Belfast in SeptemberUnited Kingdom · 252 kmHigh 15.7°C · Low 11.3°C · 70 mm rain
- Douglas in SeptemberIsle of Man · 316 kmHigh 15.1°C · Low 13.1°C · 85 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Galway) is explained once on the Galway year overview and on the Sources, method and limits page.