September weather forecastL'Islet, Guernsey
September
Weather in September
September transitions L'Islet, Guernsey into the embrace of autumn. Temperatures exhibit a downward trend throughout September, with a high of 17.3°C (63.1°F) and a low of 14.9°C (58.8°F). The winds are also characteristically gentler, dropping from August's 22.8km/h (14.2mph) to 25.7km/h (16mph). Daylight shortens by about two hours in concert with the quieting weather, signaling the season of fall approaching. The blend of fading summer warmth and encroaching autumnal coolness sets the tone for picturesque autumn landscapes.Temperature
L'Islet, Guernsey, marks the onset of September with an average high-temperature of a still refreshing 17.3°C (63.1°F), a subtle shift from August's 17.8°C (64°F). L'Islet observes an average low-temperature of 14.9°C (58.8°F) during the slightly cooler nights of September.Humidity
The average relative humidity in September is 80%.Rainfall
In L'Islet, in September, it is raining for 13.6 days, with typically 36mm (1.42") of accumulated precipitation. In L'Islet, Guernsey, during the entire year, the rain falls for 195.6 days and collects up to 554mm (21.81") of precipitation.Snowfall
In L'Islet, Guernsey, snow does not fall in February through December.Daylight
In L'Islet, Guernsey, the average length of the day in September is 12h and 36min.On the first day of September, sunrise is at 06:26 and sunset at 19:53. On the last day of the month, sunrise is at 07:09 and sunset at 18:50 BST.
Sunshine
In September, the average sunshine is 8.3h.UV index
The months with the highest UV index in L'Islet are July through September, with an average maximum UV index of 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.Note: The average daily UV index of 5 in September transforms into the following instructions:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
L'Islet, Guernsey
- Average high temperature in September: 17.3°C
The warmest month (with the highest average high temperature) is August (17.8°C).
The month with the lowest average high temperature is February (9.2°C).
- Average low temperature in September: 14.9°C
The month with the highest average low temperature is August (15.7°C).
The coldest month (with the lowest average low temperature) is February (6.9°C).
Average pressure in September
L'Islet, Guernsey
- Average pressure in September: 1017.9mbar
The month with the highest atmospheric pressure is September (1017.9mbar).
The month with the lowest atmospheric pressure is November (1011.5mbar).
Average wind speed in September
L'Islet, Guernsey
- Average wind speed in September: 25.7km/h
The windiest month (with the highest average wind speed) is December (36km/h).
The calmest month (with the lowest average wind speed) is July (21.9km/h).
Average humidity in September
L'Islet, Guernsey
- Average humidity in September: 80%
The months with the highest relative humidity are June and July (84%).
The months with the lowest relative humidity are November and December (77%).
Average rainfall in September
L'Islet, Guernsey
- Average rainfall in September: 36mm
The wettest month (with the highest rainfall) is November (78mm).
The driest month (with the least rainfall) is July (26mm).
Average rainfall days in September
L'Islet, Guernsey
- Average rainfall days in September: 13.6 days
The month with the highest number of rainy days is November (22.5 days).
The month with the least rainy days is June (11.4 days).
Average snowfall in September
L'Islet, Guernsey
- Average snowfall in September: 0mm
The month with the highest snowfall is January (2mm).
The months with the least snowfall are February, March, April, May, June, July, August, September, October, November and December (0mm).
Average snowfall days in September
L'Islet, Guernsey
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (0.3 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in September /
Average sunshine in September
L'Islet, Guernsey
- Average daylight in September: 12h and 36min
The month with the longest days is June (Average daylight: 16h and 12min).
The month with the shortest days is December (Average daylight: 8h and 12min).
- Average sunshine in September: 8h and 18min
The month with the most sunshine is July (Average sunshine: 9h and 30min).
The month with the least sunshine is December (Average sunshine: 3h and 48min).
Average sunshine days in September
L'Islet, Guernsey
- Average sunshine days in September: 13.3 days
The month with the most sunshine days is May (16.3 days).
The month with the least sunshine days is November (4.2 days).
Average UV index in September
L'Islet, Guernsey
- Average UV index in September: 5
The months with the highest UV index are July, August and September (UV index 5).
The month with the lowest UV index is February (UV index 2).
Average cloud cover in September
L'Islet, Guernsey
- Average cloud cover in September: 41
The months with the most cloud cover are January, November and December (Cloud cover 62).
The month with the least cloud cover is July (Cloud cover 38).
Average visibility in September
L'Islet, Guernsey
- Average visibility in September: 10km
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
