Roundstone Weather in September
Roundstone in September sees moderate temperatures, with highs around 17°C (63°F) and overnight lows of 12°C (54°F). Rainfall is fairly high at around 128 mm (5 in) on average, so pack waterproofs just in case.
Rainfall in Roundstone in September
On average, there are about 21 days with rain during this month, averaging 128 mm (5 in). This is a wet month with frequent and often heavy showers. Both the number of rain days and the total rainfall are high.
Temperature in Roundstone in September
In September, Roundstone gets moderate temperatures, with highs of 17°C (63°F). Nights cool to around 12°C (54°F). Temperatures can feel cooler in the morning and evening, so layering is often the best approach. Nights drop to around 12°C (54°F), which is noticeably cooler than the daytime. A light jacket for the evening is a sensible addition, and the cool nights tend to make sleeping comfortable.
Sunshine in Roundstone in September
This month sees fewer sunny days, with about 93 hours of sunshine, perfect for those who enjoy cooler temperatures.Our weather planner can help you find worldwide destinations with pleasant weather during this period. May, July and August typically offer the best weather for Roundstone.
Roundstone Temperature in September
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Roundstone Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Roundstone - and find the best time to visit.
Daily Historical Temperatures
47-year average (1976-2025)
Based on our historical records, temperatures in Roundstone typically stay consistent throughout September, with daily highs averaging around 17°C (63°F). Nights are cool, with lows typically ranging from 9°C (48°F) to 12°C (54°F).
Average temperatures in September
Daily Historical Precipitation
47-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather records for Roundstone in September
Browse day-by-day weather records for Roundstone spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Roundstone historical weather extremes in September
According to our 26 years of weather records for Roundstone, the following extremes were recorded between 1999 and 2025.
- Roundstone recorded its highest September temperature of 27°C (81°F) on September 7, 2023.
- The lowest daytime temperature in September was 11°C (52°F), recorded on September 26, 2007.
- Roundstone registered its coldest September night on September 27, 2007, with temperatures dropping to 1°C (34°F).
- The wettest September day on record brought 55 mm (2.2 in) of precipitation to Roundstone (September 11, 2015).
Best Places in Ireland in September
Find out more about the weather in Ireland and which places have the best travel conditions in this month. See all of Ireland in September →
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
What to Wear in Roundstone in September
Pleasant temperatures in September mean you can pack light but flexibel pieces. Think cotton t-shirts, comfortable walking shorts, and one warmer layer for evenings. A light sweater or denim jacket works well. Prepare for significant rainfall with proper waterproof clothing and shoes. With limited sunshine expected, sunglasses aren't a priority for packing.
What To Do in Roundstone in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
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Swimming4/10 -
Cycling5/10 -
Walking5/10 -
Camping6/10 -
Outdoor sports9/10
Roundstone 3-Day Forecast
Temperature Rainfall Sunshine Humidity
See the full Roundstone climate overview or explore weather in Ireland.
Popular in September
Where to go in September - average daytime high across popular destinations.
Westport
17°C (63°F) Doolin17°C (63°F) Kilkenny
18°C (64°F) Cork18°C (64°F) Kenmare18°C (64°F) Killarney17°C (63°F) Galway18°C (64°F) Dublin18°C (64°F) 
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