September weather forecastLlansteffan, United Kingdom
September
Weather in September
The first month of the autumn, September, is still a refreshing month in Llansteffan, United Kingdom, with an average temperature varying between 16.4°C (61.5°F) and 12.3°C (54.1°F).Temperature
September's average high-temperature is a still enjoyable 16.4°C (61.5°F), maintaining a close comparison with August's 17.4°C (63.3°F). In Llansteffan, the nocturnal temperatures throughout September show a marginal dip from the daytime averages, settling at a cool 12.3°C (54.1°F).Humidity
The months with the highest humidity are January, July through October and December, with an average relative humidity of 84%.Rainfall
In September, the rain falls for 11.6 days. Throughout September, 23mm (0.91") of precipitation is accumulated. Throughout the year, in Llansteffan, there are 165.1 rainfall days, and 303mm (11.93") of precipitation is accumulated.Snowfall
March through November are months without snowfall.Sea temperature
In Llansteffan, United Kingdom, the average seawater temperature in September is 16.6°C (61.9°F).Note: In water with a temperature of 16.6°C (61.9°F), swimming is not a joy for most people. The challenge of controlling breathing increases as the temperature dips from 21°C (69.8°F) to 15°C (59°F).
Daylight
The average length of the day in September is 12h and 38min.On the first day of the month, sunrise is at 6:30 am and sunset at 8:04 pm. On the last day of September, in Llansteffan, sunrise is at 7:17 am and sunset at 6:57 pm BST.
Sunshine
In Llansteffan, United Kingdom, the average sunshine in September is 7h.UV index
The months with the highest UV index in Llansteffan are May through September, with an average maximum UV index of 4. A UV Index reading of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for average individuals.Note: A typical high UV index of 4 in September suggests the following recommendations:
Undertake precautions - Obligation exists to protect against skin and eye damage. The Sun's radiation is especially intense around midday; try to stay in shade during this period. Stay sun-safe with clothing that is both closely woven and worn loosely.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Llansteffan, United Kingdom
- Average high temperature in September: 16.4°C
The warmest month (with the highest average high temperature) is July (17.8°C).
The months with the lowest average high temperature are January and February (7.9°C).
- Average low temperature in September: 12.3°C
The month with the highest average low temperature is August (13.8°C).
The coldest month (with the lowest average low temperature) is February (4.8°C).
Average pressure in September
Llansteffan, United Kingdom
- Average pressure in September: 1016.6mbar
The month with the highest atmospheric pressure is May (1016.7mbar).
The month with the lowest atmospheric pressure is November (1009.7mbar).
Average wind speed in September
Llansteffan, United Kingdom
- Average wind speed in September: 19km/h
The windiest month (with the highest average wind speed) is December (25.2km/h).
The calmest month (with the lowest average wind speed) is June (15.9km/h).
Average humidity in September
Llansteffan, United Kingdom
- Average humidity in September: 84%
The months with the highest relative humidity are January, July, August, September, October and December (84%).
The month with the lowest relative humidity is April (81%).
Average rainfall in September
Llansteffan, United Kingdom
- Average rainfall in September: 23mm
The wettest month (with the highest rainfall) is December (35mm).
The driest months (with the least rainfall) are April and May (15mm).
Average rainfall days in September
Llansteffan, United Kingdom
- Average rainfall days in September: 11.6 days
The month with the highest number of rainy days is December (17.1 days).
The month with the least rainy days is April (11.5 days).
Average snowfall in September
Llansteffan, United Kingdom
- Average snowfall in September: 0mm
The month with the highest snowfall is January (6mm).
The months with the least snowfall are March, April, May, June, July, August, September, October and November (0mm).
Average snowfall days in September
Llansteffan, United Kingdom
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (1.1 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).
Average sea temperature in September
Llansteffan, United Kingdom
- Average sea temperature in September: 16.6°C
The best month for swimming (with the highest average sea temperature) is August (16.8°C).
The coldest month (with the lowest average sea temperature) is March (8.3°C).
Average daylight in September /
Average sunshine in September
Llansteffan, United Kingdom
- Average daylight in September: 12h and 36min
The month with the longest days is June (Average daylight: 16h and 36min).
The month with the shortest days is December (Average daylight: 7h and 54min).
- Average sunshine in September: 7h and 0min
The months with the most sunshine are April and May (Average sunshine: 8h and 18min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Llansteffan, United Kingdom
- Average sunshine days in September: 13.4 days
The month with the most sunshine days is March (15.2 days).
The month with the least sunshine days is July (9.2 days).
Average UV index in September
Llansteffan, United Kingdom
- 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 and December (UV index 2).
Average cloud cover in September
Llansteffan, United Kingdom
- Average cloud cover in September: 51
The month with the most cloud cover is December (Cloud cover 63).
The months with the least cloud cover are April and May (Cloud cover 46).
Average visibility in September
Llansteffan, United Kingdom
- Average visibility in September: 10km
The months with the highest visibility are January, February, March, April, June, August, September, October, November and December (10km).
The months with the lowest visibility are May and July (9km).
