September weather forecastSaint Johns, Guernsey
September
Weather in September
The first month of the autumn, September, is still a refreshing month in Saint Johns, Guernsey, with an average temperature fluctuating between 15.4°C (59.7°F) and 17.2°C (63°F).Temperature
September's average high-temperature is a still refreshing 17.2°C (63°F), maintaining a close comparison with August's 17.8°C (64°F). Saint Johns observes a minimal variance in temperature, with a consistent average low of 15.4°C (59.7°F) during the nights of September.Humidity
The average relative humidity in September is 80%.Rainfall
In Saint Johns, in September, during 13.5 rainfall days, 31mm (1.22") of precipitation is typically accumulated. Throughout the year, there are 196.3 rainfall days, and 557mm (21.93") of precipitation is accumulated.Snowfall
February through December are months without snowfall in Saint Johns.Daylight
In Saint Johns, the average length of the day in September is 12h and 36min.On the first day of the month, sunrise is at 06:26 and sunset at 19:53. On the last day of September, sunrise is at 07:09 and sunset at 18:50 BST.
Sunshine
In September, the average sunshine is 8.4h.UV index
July through September, with an average maximum UV index of 5, are months with the highest UV index. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for average individuals.Note: The daily high UV index of 5 during September translates into the following recommendations:
Exercise prevention - Precautions against solar damage are endorsed. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Saint Johns, Guernsey
- Average high temperature in September: 17.2°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: 15.4°C
The month with the highest average low temperature is August (15.8°C).
The coldest month (with the lowest average low temperature) is February (7°C).
Average pressure in September
Saint Johns, 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
Saint Johns, Guernsey
- Average wind speed in September: 25.8km/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
Saint Johns, 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
Saint Johns, Guernsey
- Average rainfall in September: 31mm
The wettest month (with the highest rainfall) is November (87mm).
The driest month (with the least rainfall) is July (26mm).
Average rainfall days in September
Saint Johns, Guernsey
- Average rainfall days in September: 13.5 days
The month with the highest number of rainy days is November (22.8 days).
The month with the least rainy days is June (11.5 days).
Average snowfall in September
Saint Johns, 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
Saint Johns, 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
Saint Johns, 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 24min
The month with the most sunshine is July (Average sunshine: 9h and 42min).
The months with the least sunshine are January, November and December (Average sunshine: 3h and 54min).
Average sunshine days in September
Saint Johns, Guernsey
- Average sunshine days in September: 13.1 days
The month with the most sunshine days is May (16.3 days).
The month with the least sunshine days is November (4 days).
Average UV index in September
Saint Johns, 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
Saint Johns, Guernsey
- Average cloud cover in September: 41
The months with the most cloud cover are November and December (Cloud cover 63).
The month with the least cloud cover is July (Cloud cover 37).
Average visibility in September
Saint Johns, 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).
