Dalkey Weather in September

Dalkey in September averages 17°C (63°F) during the day and 11°C (52°F) at night. This is part of the summer season, and quite a bit of rainfall is expected this month.

Rainfall in Dalkey in September

On average, there are about 15 days with rain during this month, averaging 81 mm (3.2 in). Rain this month is fairly typical, a standard mix of wet and dry days with no particularly heavy or persistent showers.

Temperature in Dalkey in September

Dalkey in September gets highs of 17°C (63°F) during the day and drops to 11°C (52°F) at night. The summer season takes place during September. Conditions are often most pleasant around the middle of the day. At 11°C (52°F) overnight, it can feel quite a bit cooler after dark. Worth packing something warmer for evenings, but the cooler temperatures are ideal for sleeping.

Sunshine in Dalkey in September

The month brings about 128 hours of sunlight, offering a comfortable mix of sun and overcast.

Wind Speed in Dalkey in September

In September, average wind speeds reach 4 m/s (8 knots), leading to light to moderate breezes. Conditions vary from day to day, with both calm and windier periods.

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.

Should you favor a climate that's both dry and comfortably warm, July and August typically offer the most agreeable circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Ireland, check out our Dalkey's climate page.

Dalkey Temperature in September

Min Temperature 11°C (52°F)  

Max Temperature 17°C (63°F)  

Water Temperature 15°C (59°F) *  

Chance of Rain 50%  

Precipitation 81 mm (3.2 in)  

Rainy days 15 days  

Humidity 71% *  

Windspeed 4 m/s (8 knots) *  

Sunshine 128 hours *  

Percentage Sunshine 33% *  

* Data from: Dublin, Ireland (19 KM, 12 Miles).

Daily Historical Temperatures

50-year average (1976-2025)

Based on our historical records, temperatures in Dalkey 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 11°C (52°F).

Average temperatures in September

‹ Select year to compare to 2026 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 ›

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

‹ January February March April May June July August September October November December ›

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

‹ Select year to compare to 2026 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 ›

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

‹ January February March April May June July August September October November December ›

Historical weather for Dalkey in September

Browse day-by-day weather records for Dalkey spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.

Historical weather Temperatures Precipitation

‹ 2026 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 ›

‹ January February March April May June July August September October November December ›

Dalkey historical weather extremes in September

According to our 49 years of weather records for Dalkey, the following extremes were recorded between 1976 and 2025.

• Dalkey recorded its highest September temperature of 26°C (79°F) on September 8, 2023.
• On September 17, 2013, Dalkey saw its coldest September day with temperatures maxing out at 10°C (50°F).
• The coldest night in September in Dalkey was on September 22, 2012, with a minimum of 1°C (34°F).

What to Wear in Dalkey 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. Expect water temperatures of around 15°C (59°F), which is definitely too cold for comfortable swimming. Your luggage space is better used for other items. Bring sunglasses since you'll have some sunny periods throughout the month

What To Do in Dalkey in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

6/10

Cycling

6/10

Walking

6/10

Camping

8/10

Outdoor sports

9/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Ireland, check out our Dalkey's climate page.

More climate data for Dalkey

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

See the full Dalkey climate overview or explore weather in Ireland.