September weather forecastLlanelli, United Kingdom
September weather for Llanelli, United Kingdom: September, the first month of the autumn in Llanelli, is still a comfortable month, with an average temperature fluctuating between 16.4°C (61.5°F) and 11.9°C (53.4°F). In Llanelli, United Kingdom, in September, the average water temperature is 16.6°C (61.9°F).
September
Weather in September
September, the first month of the autumn in Llanelli, is still a comfortable month, with an average temperature fluctuating between 16.4°C (61.5°F) and 11.9°C (53.4°F).Temperature
Llanelli's transition from August to September introduces an average high-temperature of a still comfortable 16.4°C (61.5°F), marking an insignificant variation from the 17.5°C (63.5°F). Llanelli reports an average low-temperature of 11.9°C (53.4°F) during the subtly cooler September nights.Humidity
In September, the average relative humidity in Llanelli is 84%.Rainfall
In September, the rain falls for 17.5 days. Throughout September, 54mm (2.13") of precipitation is accumulated. In Llanelli, during the entire year, the rain falls for 219.6 days and collects up to 745mm (29.33") of precipitation.Snowfall
In Llanelli, snow does not fall in April through November.Sea temperature
In Llanelli, in September, the average water temperature is 16.6°C (61.9°F).Note: In water of 16.6°C (61.9°F), the majority of people do not enjoy swimming. Breathing becomes increasingly hard to manage as the temperature drops 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 September, sunrise is at 6:29 am and sunset at 8:03 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 6:56 pm BST.
Sunshine
The average sunshine in September is 7h.UV index
The months with the highest UV index in Llanelli are May through September, with an average maximum UV index of 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for the ordinary person.Note: The UV index of 4 in September translates into these instructions:
Be vigilant - A duty to shield skin and eyes from injury exists. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Llanelli, 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 month with the lowest average high temperature is February (7.7°C).
- Average low temperature in September: 11.9°C
The month with the highest average low temperature is August (13.6°C).
The coldest month (with the lowest average low temperature) is February (4.5°C).
Average pressure in September
Llanelli, 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
Llanelli, United Kingdom
- Average wind speed in September: 18.1km/h
The windiest month (with the highest average wind speed) is December (23.9km/h).
The calmest month (with the lowest average wind speed) is June (15.4km/h).
Average humidity in September
Llanelli, United Kingdom
- Average humidity in September: 84%
The months with the highest relative humidity are January, August, October, November and December (85%).
The month with the lowest relative humidity is April (81%).
Average rainfall in September
Llanelli, United Kingdom
- Average rainfall in September: 54mm
The wettest month (with the highest rainfall) is December (84mm).
The driest month (with the least rainfall) is May (37mm).
Average rainfall days in September
Llanelli, United Kingdom
- Average rainfall days in September: 17.5 days
The month with the highest number of rainy days is December (21.5 days).
The month with the least rainy days is April (15.1 days).
Average snowfall in September
Llanelli, United Kingdom
- Average snowfall in September: 0mm
The month with the highest snowfall is December (8mm).
The months with the least snowfall are April, May, June, July, August, September, October and November (0mm).
Average snowfall days in September
Llanelli, United Kingdom
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (1.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in September
Llanelli, 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
Llanelli, 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 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Llanelli, United Kingdom
- Average sunshine days in September: 9.7 days
The month with the most sunshine days is May (12.8 days).
The month with the least sunshine days is August (6.5 days).
Average UV index in September
Llanelli, 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, November and December (UV index 2).
Average cloud cover in September
Llanelli, 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
Llanelli, United Kingdom
- Average visibility in September: 9km
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).
