Letterkenny in september: average Weather, Temperature and Climate
Weather in Letterkenny in september 2025
The weather in Letterkenny in september comes from statistical datas on the past years. You can view the weather statistics for all the month, but also by clicking on the tabs for the beginning, the middle and the end of the month.
Average weather throughout september
bad weather
Weather at 6am
50°F
Fog
45% of time
26%
12%
9%
Weather at 12pm
61°F
Cloudy
45% of time
19%
18%
11%
Weather at 6pm
56°F
Cloudy
31% of time
27%
15%
15%
Weather at 3am
50°F
37%
17%
15%
15%
Evolution of daily average temperature and precipitation in Letterkenny in september
These charts show the evolution of average minimum/maximum temperatures as well as average daily precipitation volume in Letterkenny in september.
The climate of Letterkenny in september is bad
The weather in september in Letterkenny is wet (with 2.3in of precipitation over 3 days). The weather is better from the previous month since in august it receives an average of 3.2in of precipitation over 4 days.
The climate is fairly fresh there september, but it is endurable when dressing hot. The thermometer averaged maximum of 61°F. On average, the recorded minimum temperature is 50°F. Thus, the mean temperature average in september in Letterkenny is 56°F. Note that seasonal normals in contrast with those observed in Letterkenny in september with a maximum record of 77°F in 2021 and a minimum record of 31°F in 2010. You can hope to have about 7 days with temperatures over 65°F, or 23% of time.
On this month of september, day length in Letterkenny is generally 12:43. Sunrise is at 06:04 and sets at 18:47.
With an unfavorable weather, september is not recommended to go in that area.
September: another location in Ireland?
If you want to go to Ireland in september, there are destinations with better weather than Letterkenny:
In september, Dublin, Cork, Ardmore, Dalkey Island, Rosslare and Tramore have good weather.
Finally, Galway, Belmullet, Connemara National Park, Dingle, Dundalk and Dungloe have a tolerable climate, but better than Letterkenny.
Seasonal average climate and temperature of Letterkenny in september
Check below seasonal norms These statistics are set from the weather statements of the last years of september.
| September | |||||
| Outside temperature | |||||
| Average temperature | 56°F | ||||
| Highest temperature | 61°F | ||||
| Lowest temperature | 50°F | ||||
| Highest record temperature | 77°F (2021) | ||||
| Lowest record temperature | 31°F (2010) | ||||
| Number of days at +65°F | 7 day(s) (23%) | ||||
| Sea temperature | |||||
| Average sea temperature | 58°F | ||||
| Lowest sea temperature | 56°F | ||||
| Highest sea temperature | 60°F | ||||
| Wind | |||||
| Wind speed | 19km/h | ||||
| Wind temperature | 47°F | ||||
| Precipitation (rainfall) | |||||
| Rainfall | 2.3in | ||||
| Number of days with rainfall | 3 day(s) (8%) | ||||
| Record daily rainfall | 1.2in (2019) | ||||
| Other climate data | |||||
| Humidity | 96% | ||||
| Visibility | 7.44km | ||||
| Cloud cover | 67% | ||||
| UV index | 4 | ||||
| Daily sunshine hours | 10 | ||||
| Sunrise and sunset | |||||
| Time of sunrise | 06:04 | ||||
| Time of sunset | 18:47 | ||||
| Length of day | 12:43 | ||||
| Our opinion about the weather in september | |||||
| Our opinion at whereandwhen.net | bad | ||||
How was the weather last september?
Here is the day by day recorded weather in Letterkenny in september 2024:
54°F to 65°F
56°F to 59°F
54°F to 58°F
52°F to 58°F
49°F to 61°F
56°F to 68°F
56°F to 70°F
56°F to 58°F
50°F to 58°F
50°F to 56°F
47°F to 52°F
49°F to 52°F
41°F to 49°F
56°F to 61°F
54°F to 61°F
49°F to 61°F
54°F to 70°F
52°F to 67°F
50°F to 68°F
52°F to 67°F
52°F to 63°F
50°F to 63°F
52°F to 56°F
50°F to 52°F
47°F to 50°F
47°F to 49°F
49°F to 50°F
49°F to 54°F
47°F to 56°F
49°F to 52°F
Map: other cities in Ireland in september
Cities near Letterkenny:
| Ballybofey in september | bad weather |
| Buncrana in september | tolerable weather |
| Dunfanaghy in september | tolerable weather |
| Derrybeg in september | tolerable weather |
| Dungloe in september | tolerable weather |
| Donegal in september | tolerable weather |
| Moville in september | tolerable weather |
| Malin Head in september | tolerable weather |
| Ballyshannon in september | tolerable weather |
| Killybegs in september | tolerable weather |
| Bundoran in september | tolerable weather |
| Gleann Cholm Cille in september | tolerable weather |
Click over cities on the map for information about the weather in september.
Letterkenny
perfect weather
good
tolerable
bad
very bad
Weather data for Letterkenny in september:
Weather data for Letterkenny for september are derived from an average of the weather forecast since 2009 in Letterkenny. There is a margin of error and these forecasts are to be considered as general information only. The weather in Letterkenny can vary slightly from year to year, but this data should limit surprises. So you can pack your bags or check for the best time in year to go to Letterkenny.