September weather forecastPortinfer, Jersey
September
Weather in September
September ushers into Portinfer the start of autumn, with temperatures slowly decreasing from the summer peak. The decline occurs as daylight hours recede to 12.6 hours with pressure registering at 1018mb. However, wind speed starts climbing again, bringing a slight chill in the air. Even though rainfall slightly decreases, the cloud cover remains constant, ensuring autumnal vibes. The UV index falls to 4, giving a little respite from the intense summer sun.Temperature
September's average high-temperature stands at a still enjoyable 17.4°C (63.3°F), showing little deviation from August's 18.1°C (64.6°F). In Portinfer, September is characterized by an average low-temperature of 15.6°C (60.1°F), indicating a minor drop from daytime highs.Humidity
In Portinfer, Jersey, the average relative humidity in September is 79%.Rainfall
In September, the rain falls for 13.4 days. Throughout September, 29mm (1.14") of precipitation is accumulated. In Portinfer, during the entire year, the rain falls for 191.6 days and collects up to 531mm (20.91") of precipitation.Snowfall
February, April through October and December are months without snowfall.Daylight
In Portinfer, the average length of the day in September is 12h and 35min.On the first day of September, sunrise is at 06:25 and sunset at 19:51. On the last day of the month, sunrise is at 07:07 and sunset at 18:49 BST.
Sunshine
In Portinfer, the average sunshine in September is 8.6h.UV index
In Portinfer, Jersey, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum daily UV index, 4 in September, converts into the following recommendations:
Prioritize safety - Recommendations to avert sunburn are shared. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Portinfer, Jersey
- Average high temperature in September: 17.4°C
The warmest month (with the highest average high temperature) is August (18.1°C).
The month with the lowest average high temperature is February (9°C).
- Average low temperature in September: 15.6°C
The month with the highest average low temperature is August (16.3°C).
The coldest month (with the lowest average low temperature) is February (6.9°C).
Average pressure in September
Portinfer, Jersey
- Average pressure in September: 1018mbar
The month with the highest atmospheric pressure is September (1018mbar).
The month with the lowest atmospheric pressure is November (1011.8mbar).
Average wind speed in September
Portinfer, Jersey
- Average wind speed in September: 23.9km/h
The windiest month (with the highest average wind speed) is December (34.3km/h).
The calmest month (with the lowest average wind speed) is July (20.6km/h).
Average humidity in September
Portinfer, Jersey
- Average humidity in September: 79%
The month with the highest relative humidity is June (84%).
The months with the lowest relative humidity are February, November and December (78%).
Average rainfall in September
Portinfer, Jersey
- Average rainfall in September: 29mm
The wettest month (with the highest rainfall) is November (74mm).
The driest months (with the least rainfall) are May and July (27mm).
Average rainfall days in September
Portinfer, Jersey
- Average rainfall days in September: 13.4 days
The month with the highest number of rainy days is November (20.7 days).
The month with the least rainy days is May (12.7 days).
Average snowfall in September
Portinfer, Jersey
- Average snowfall in September: 0mm
The months with the highest snowfall are January, March and November (1mm).
The months with the least snowfall are February, April, May, June, July, August, September, October and December (0mm).
Average snowfall days in September
Portinfer, Jersey
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are February and March (0.3 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Portinfer, Jersey
- 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 18min).
- Average sunshine in September: 8h and 36min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Portinfer, Jersey
- Average sunshine days in September: 14.1 days
The month with the most sunshine days is May (15.3 days).
The month with the least sunshine days is November (6.5 days).
Average UV index in September
Portinfer, Jersey
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 5).
The month with the lowest UV index is February (UV index 2).
Average cloud cover in September
Portinfer, Jersey
- Average cloud cover in September: 39
The months with the most cloud cover are January, November and December (Cloud cover 61).
The month with the least cloud cover is July (Cloud cover 36).
Average visibility in September
Portinfer, Jersey
- 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).
