Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average sea temperature in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The transition from August to September sees an average high-temperature of a mild 15.6°C (60.1°F), indicating a minor variance from the prior month. A consistent nighttime average temperature of 10.6°C (51.1°F) is maintained during September.Humidity
In Portmarnock, the average relative humidity in September is 85%.Rainfall
In September, in Portmarnock, the rain falls for 10.9 days. Throughout September, 25mm (0.98") of precipitation is accumulated. In Portmarnock, during the entire year, the rain falls for 159.4 days and collects up to 362mm (14.25") of precipitation.Snowfall
April through October are months without snowfall.Sea temperature
In Portmarnock, the average seawater temperature in September is 14.8°C (58.6°F).Note: Swimming in 14.8°C (58.6°F) at temperatures under 10°C (50°F) requires thermal swimsuits; otherwise, one can face cold shock and breathing difficulty. Even brief immersion at 13°C (55.4°F) feels frosty.
Daylight
The average length of the day in September in Portmarnock is 12h and 41min.On the first day of September in Portmarnock, sunrise is at 6:34 am and sunset at 8:13 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 7:03 pm IST.
Sunshine
In September, the average sunshine is 7h.UV index
May through September, with an average maximum UV index of 4, are months with the highest UV index in Portmarnock, Ireland. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for average individuals.Note: In September, an average UV index of 4 transforms into the following instructions:
Take necessary precautions - Protection from skin and eye injury is mandatory. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days.
Frequently asked questions
What is the average September temperature in Portmarnock?
What is the average humidity in September in Portmarnock?
How many days does it rain in September in Portmarnock?
When it does not snow in Portmarnock?
What is the sea water temperature in September in Portmarnock?
What is the average length of the day in September in Portmarnock?
When are sunrise and sunset in September in Portmarnock?
How long on average sun shines in September in Portmarnock?
What is the month with the highest UV index in Portmarnock?
What is the UV index reading in September in Portmarnock?
Average temperature in September
Portmarnock, Ireland
- Average high temperature in September: 15.6°C
The warmest month (with the highest average high temperature) is July (17.4°C).
The month with the lowest average high temperature is January (7.6°C).
- Average low temperature in September: 10.6°C
The months with the highest average low temperature are July and August (12.1°C).
The coldest months (with the lowest average low temperature) are February and March (3.9°C).
Average pressure in September
Portmarnock, Ireland
- Average pressure in September: 1015.2mbar
The month with the highest atmospheric pressure is May (1016mbar).
The month with the lowest atmospheric pressure is November (1008.2mbar).
Average wind speed in September
Portmarnock, Ireland
- Average wind speed in September: 18.1km/h
The windiest month (with the highest average wind speed) is January (24.2km/h).
The calmest month (with the lowest average wind speed) is June (15.2km/h).
Average humidity in September
Portmarnock, Ireland
- Average humidity in September: 85%
The months with the highest relative humidity are July and December (86%).
The months with the lowest relative humidity are March, April and May (83%).
Average rainfall in September
Portmarnock, Ireland
- Average rainfall in September: 25mm
The wettest month (with the highest rainfall) is November (51mm).
The driest month (with the least rainfall) is May (19mm).
Average rainfall days in September
Portmarnock, Ireland
- Average rainfall days in September: 10.9 days
The month with the highest number of rainy days is July (17.1 days).
The month with the least rainy days is February (10.7 days).
Average snowfall in September
Portmarnock, Ireland
- Average snowfall in September: 0mm
The month with the highest snowfall is December (12mm).
The months with the least snowfall are April, May, June, July, August, September and October (0mm).
Average snowfall days in September
Portmarnock, Ireland
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (2.1 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in September
Portmarnock, Ireland
- Average sea temperature in September: 14.8°C
The best month for swimming (with the highest average sea temperature) is August (14.9°C).
The coldest month (with the lowest average sea temperature) is March (8.4°C).
Average daylight in September /
Average sunshine in September
Portmarnock, Ireland
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 54min).
The month with the shortest days is December (Average daylight: 7h and 36min).
- Average sunshine in September: 7h and 0min
The months with the most sunshine are April, May and June (Average sunshine: 7h and 30min).
The months with the least sunshine are January, February and November (Average sunshine: 4h and 18min).
Average sunshine days in September
Portmarnock, Ireland
- Average sunshine days in September: 16.4 days
The months with the most sunshine days are January and December (16.8 days).
The month with the least sunshine days is July (11 days).
Average UV index in September
Portmarnock, Ireland
- Average UV index in September: 4
The months with the highest UV index are May, June, July, August and September (UV index 4).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Portmarnock, Ireland
- Average cloud cover in September: 50
The months with the most cloud cover are January and February (Cloud cover 57).
The months with the least cloud cover are April and September (Cloud cover 50).
Average visibility in September
Portmarnock, Ireland
- Average visibility in September: 9km
The months with the highest visibility are January, February, March, October, November and December (10km).
The months with the lowest visibility are April, May, June, July, August and September (9km).
Portmarnock, Ireland
Weather forecast for your location
2. Allow the app to use your location
