Cahersiveen Weather in September
September in Cahersiveen averages 17°C (63°F) during the day and 12°C (54°F) at night. Quite a bit of rainfall is typical this month, with around 116 mm (4.6 in) on average. An umbrella is a good idea.
Rainfall in Cahersiveen in September
The climate data from previous years indicates about 20 days of rain, averaging 116 mm (4.6 in) for the month. Rain falls regularly this month and can be quite heavy when it does. Showers can be substantial, so waterproof gear is a good idea.
Temperature in Cahersiveen in September
September in Cahersiveen sees highs of 17°C (63°F) and lows of 12°C (54°F) overnight. This creates a mild day-to-night pattern that is generally easy to manage with the right clothing. With overnight lows of 12°C (54°F), evenings can feel noticeably cooler than the daytime. An extra layer is a good idea, though the cool air makes for a good night's sleep.
Sunshine in Cahersiveen in September
You can expect a moderate amount of sunlight, with approximately 118 hours. This means a pleasant mix of sun and overcast.
Wind Speed in Cahersiveen in September
September has wind speeds averaging 5 m/s (10 knots). You can expect gentle to moderate winds that move small trees and make flags wave steadily on typical days. Conditions typically range from light breezes to moderate winds.
Average water temperature in September
The water is 15°C (59°F) this month — cool enough to feel refreshing on a warm day, but cold enough that most people won't stay in for long without a wetsuit.If you prefer enjoying temperate temperatures and rain-free days, June, July and August typically offer the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Ireland, check out our Cahersiveen's climate page.
Cahersiveen Temperature in September
Min Temperature
12°C (54°F)
Max Temperature
17°C (63°F)
Water Temperature
15°C (59°F) *
Chance of Rain
67%
Precipitation
116 mm (4.6 in)
Rainy days
20 days
Humidity
77% *
Windspeed
5 m/s (10 knots) *
Sunshine
118 hours *
Percentage Sunshine
30% *
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Cahersiveen typically stay consistent throughout September, with daily highs averaging around 17°C (63°F). Nights are cool, with lows typically ranging from 11°C (52°F) to 13°C (55°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Cahersiveen in September
Browse day-by-day weather records for Cahersiveen spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Cahersiveen historical weather extremes in September
Based on 49 years of weather observations (1976-2025), these are the most extreme conditions recorded in Cahersiveen.
- On September 5, 1991, temperatures climbed to 28°C (82°F), marking the warmest September day on record.
- On September 20, 2018, Cahersiveen saw its coldest September day with temperatures maxing out at 12°C (54°F).
- The lowest overnight temperature recorded in September was 3°C (37°F) (September 26, 1992).
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
pleasant
tolerable
unpleasant
poor
What to Wear in Cahersiveen in September
Comfortable temperatures call for an easy wardrobe in September. Pack summer basics like t-shirts and shorts, but include a light jacket for cooler moments. A pair of comfortable walking shoes is essential. Expect heavy rainfall, so bring good rain protection and waterproof bags. The water temperature sits at about 15°C (59°F), which is too chilly for most people to enjoy swimming. Leave the swimsuit at home unless you love cold water. It won't hurt to bring your sunglasses along, as you'll see some sunny periods.What To Do in Cahersiveen in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Ireland, check out our Cahersiveen's climate page.
Temperature Rainfall Sunshine Humidity Wind Speed Water Temp
See the full Cahersiveen climate overview or explore weather in Ireland.
