Weather in September
September sees a reduction in sea temperature to 15.3°C (59.5°F) in Arklow while experiencing comfortable weather. Reductions in daylight hours to 12.7 signal the arrival of autumn. Typically, the weather remains warm and dry with shorter evenings. The temperatures gradually cool over the month as the summer heat subsides, marking a slow transition towards cooler autumn.
Note: When the surface water temperature is 15.3°C (59.5°F), most do not enjoy swimming. Breathing control becomes more complex as temperatures drop below 21°C (69.8°F).
On the first day of September, sunrise is at 6:36 am and sunset at 8:12 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 7:03 pm IST.
Sea temperature
September is the month with the warmest seawater, with an average sea temperature of 15.3°C (59.5°F).Note: When the surface water temperature is 15.3°C (59.5°F), most do not enjoy swimming. Breathing control becomes more complex as temperatures drop below 21°C (69.8°F).
Daylight
The average length of the day in September is 12h and 40min.On the first day of September, sunrise is at 6:36 am and sunset at 8:12 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 7:03 pm IST.
Updated: Jun 14, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
When is the sea warmest?
September is the month with the warmest seawater, with an average sea temperature of 15.3°C (59.5°F).
What is the sea temperature in September?
In September, the average sea temperature in Arklow is 15.3°C (59.5°F). For most, swimming in 15.3°C (59.5°F) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 21°C (69.8°F) to 15°C (59°F).
What is the average length of the day in September?
The average day length in September in Arklow is 12h and 40min.
When is the sunrise / sunset in September?
On the first day of September in Arklow, Ireland, sunrise is at 6:36 am and sunset at 8:12 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 7:03 pm IST.
Average sea temperature in September
Arklow, Ireland
- Average sea temperature in September: 15.3°C
The best month for swimming (with the highest average sea temperature) is September (15.3°C).
The coldest month (with the lowest average sea temperature) is March (8.5°C).
Average daylight in September
Arklow, Ireland
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 48min).
The month with the shortest days is December (Average daylight: 7h and 42min).
Arklow, Ireland
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