Weather in September
Temperature
The advent of September denotes an average high-temperature of a still enjoyable 16.7°C (62.1°F), subtly different from August's 18.5°C (65.3°F). In Londonderry, September nights witness a steady temperature drop to a chilly 9.8°C (49.6°F).Rainfall
In Londonderry, United Kingdom, in September, during 13 rainfall days, 69mm (2.72") of precipitation is typically accumulated. Throughout the year, in Londonderry, there are 170 rainfall days, and 853mm (33.58") of precipitation is accumulated.Sea temperature
In Londonderry, in September, the average water temperature is 14.3°C (57.7°F).Note: It is life-risking to swim in 14.3°C (57.7°F). Briefly staying in 13°C (55.4°F) waters feels unsettling, and temperatures below 10°C (50°F) might result in cold shock and loss of breath control, hinging on personal endurance.
Daylight
In Londonderry, United Kingdom, the average length of the day in September is 12h and 43min.On the first day of the month, sunrise is at 6:36 am and sunset at 8:21 pm. On the last day of September, in Londonderry, sunrise is at 7:30 am and sunset at 7:07 pm BST.
Sunshine
In Londonderry, the average sunshine in September is 4h.UV index
In September, the average daily maximum UV index in Londonderry is 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the average person.Note: The daily high UV index of 3 in September translates into this advice:
Act with care - Obligation to protect against skin and eye damage is highlighted. For skin protection, it's recommended to minimize Sun exposure during its peak hours around midday. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Frequently asked questions
What is the temperature in September in Londonderry?
How many days does it rain in September in Londonderry?
How cold is the water in September in Londonderry?
How many hours of daylight does Londonderry have in September?
What time are sunrise and sunset in September in Londonderry?
How long on average sun shines in September in Londonderry?
What is the UV index intensity in September in Londonderry?
Average temperature in September
Londonderry, United Kingdom
- Average high temperature in September: 16.7°C
The warmest month (with the highest average high temperature) is July (18.9°C).
The months with the lowest average high temperature are January and December (8°C).
- Average low temperature in September: 9.8°C
The month with the highest average low temperature is July (11.6°C).
The coldest month (with the lowest average low temperature) is February (2.1°C).
Average rainfall in September
Londonderry, United Kingdom
- Average rainfall in September: 68.7mm
The wettest month (with the highest rainfall) is October (89mm).
The driest month (with the least rainfall) is May (51.2mm).
Average rainfall days in September
Londonderry, United Kingdom
- Average rainfall days in September: 13 days
The month with the highest number of rainy days is November (19 days).
The month with the least rainy days is June (11 days).
Average sea temperature in September
Londonderry, United Kingdom
- Average sea temperature in September: 14.3°C
The best month for swimming (with the highest average sea temperature) is August (14.7°C).
The coldest month (with the lowest average sea temperature) is March (8.7°C).
Average daylight in September /
Average sunshine in September
Londonderry, United Kingdom
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 17h and 18min).
The month with the shortest days is December (Average daylight: 7h and 18min).
- Average sunshine in September: 4h and 0min
The month with the most sunshine is May (Average sunshine: 6h and 30min).
The month with the least sunshine is December (Average sunshine: 1h and 12min).
Average UV index in September
Londonderry, United Kingdom
- Average UV index in September: 3
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 0).
Londonderry, United Kingdom
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