SeasonMapKillarney weather in September
Ireland
September in Killarney: cool, rainy, with clean air — an excellent time to visit.
#6 of 12 months in Killarney · #639 of 1383 destinations to visit in September · comfort 81/100 (tier A)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Killarney in September
Other months in Killarney
Killarney's forum is candid that July weather is genuinely a grab bag — cold, rainy, calm, warm and windy have all been reported in the same month, with wetter conditions than spring and true heatwaves rare. Regulars' consistent advice is layers plus a proper rain jacket, noting July is also the single busiest month locally so accommodation books up fast regardless of forecast.
Add your own note from Killarney's card on the map.
Killarney climate normals — September
| Daytime high | 17°C / 62°F | 🙂 cool |
|---|---|---|
| Nighttime low | 11°C / 52°F | |
| Feels like (high) | 15°C / 59°F | |
| Sea temperature | 18°C / 64°F | 🧊 bracing |
| Rainfall | 107 mm / 4.2 in | 🌧 rainy |
| Rainy days | 15 days | |
| Humidity | 85% | 💦 very humid |
| Dew point | 11°C / 52°F | |
| Sunshine | 7.5 h/day | |
| Daylight | 12.6 h | |
| Wind | 19 km/h / 12 mph | |
| Air quality (US AQI) | 34 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Killarney in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Shoulder seasonschool holidays in 3 of the markets that fill it, an ordinary month(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Killarney's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherKillarney's weather peaks May–July.
Best weatherFair weatherToughest weather
What's on in Killarney in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Nature
Red deer rut
25 Sep – 25 Oct · usuallyRutting seasonThe native herd in the national park is the last wild one in Ireland, and through October the stags roar across Knockreer and the Muckross oakwoods. Keep well back; they are not tame.
Nearby, and something's on
Within 300 km of Killarney — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Killarney?
Killarney in September — FAQ
- Is September a good time to visit Killarney?
- September in Killarney: cool, rainy, with clean air — an excellent time to visit. It ranks #6 of 12 months for Killarney on SeasonMap's comfort score (81/100).
- What is the weather like in Killarney in September?
- In September, Killarney averages a daily high of 16.7°C and a low of 11.2°C, with about 107.4 mm of rain over roughly 15.2 rainy days.
- What is the air quality in Killarney in September?
- Killarney has a mean US Air Quality Index of about 34 in September.
Other months in Killarney
Compare Killarney in September
Warmer or cooler than Killarney in September
Similar destinations in Northern Europe — September
Within 300 km: Dingle's Blasket Islands boats around 1 Apr – 30 Sep, and Dublin's Culture Night around 15–25 Sep.