September weather forecast and climate
Longyearbyen, Svalbard and Jan Mayen SJ

• Average high temperature in September: 1°C

The warmest month (with the highest average high temperature) is July (7°C).
Months with the lowest average high temperature are January, February and March (-13°C).

• Average low temperature in September: -3°C

The month with the highest average low temperature is July (3°C).
The coldest month (with the lowest average low temperature) is February (-21°C).

• Average rainfall in September: 25mm

The wettest month (with the highest rainfall) is August (30mm).
The driest month (with the lowest rainfall) is May (13mm).

• Average rainfall days in September: 14 days

The month with the highest number of rainy days is August (18 days).
Months with the lowest number of rainy days are January, February and March (2 days).

• Average snowfall days in September: 11 days

Months with the highest number of snowfall days are November and December (22 days).
The month with the lowest number of snowfall days is July (1 days).

• Average sea temperature in September: 5°C

The best month for swimming (with the highest average sea temperature) is August (6°C).
Coldest months (with the lowest average sea temperature) are February and April (1°C).

• Average daylight in September: 14.4h

Months with the longest days are May, June and July (Average daylight: 24h).
Months with shortest days are January, November and December (Average daylight: 0h).

• Average sunshine in September: 2.5h

The month with most sunshine is May (Average sunshine: 8.2h).
Months with least sunshine are January, February, November and December (Average sunshine: 0).

• Average UV index in September: 1

Months with the highest UV index are May, June and July (UV index 2).
Months with the lowest UV index are January, February, March, October, November and December (UV index 0).