Longyearbyen
Svalbard and Jan Mayen
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Longyearbyen, Svalbard and Jan Mayen

The frozen Arctic Blue Sea overlooking the snow-covered mountains in the background, on a sunny winter morning, in Longyearbyen, Svalbard and Jan Mayen
The frozen Arctic Blue Sea overlooking the snow-covered mountains in the background, on a sunny winter morning, in Longyearbyen, Svalbard and Jan Mayen

Rainfall

In Longyearbyen, Svalbard and Jan Mayen, during September, the rain falls for 14 days and regularly aggregates up to 25mm (0.98") of precipitation. Throughout the year, there are 86 rainfall days, and 271mm (10.67") of precipitation is accumulated.

Snowfall

Months with snowfall are January through December. In Longyearbyen, during September, snow falls for 11 days. In Longyearbyen, during the entire year, snow falls for 176 days.

Sea temperature

In Longyearbyen, the average seawater temperature is 5°C (41°F).
Note: Swimming in 5°C (41°F) is considered life-threatening. Even a few minutes in 13°C (55.4°F) water is uncomfortable, and swimming below 10°C (50°F) may cause total loss of breathing control and cold shock, depending on a person's physique.

Daylight

In Longyearbyen, the average length of the day in September is 14.4h.

Sunshine

In Longyearbyen, the average sunshine in September is 2.5h.

UV index

In September, the average daily maximum UV index is 1. A UV Index estimate of 2, and below, represents a low threat to health from unsafe exposure to the UV radiation for the average person.
Note: The daily maximum UV index of 1 interpret into the following advice:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.

How many days does it rain in September in Longyearbyen?

In Longyearbyen, during September, the rain falls for 14 days and regularly aggregates up to 25mm (0.98") of precipitation.

How many days does it snow in September in Longyearbyen?

In September, in Longyearbyen, snow falls for 11 days.

How cold is the water in September in Longyearbyen?

In Longyearbyen, in September, the average water temperature is 5°C (41°F). Swimming in 5°C (41°F) is considered dangerous. Unprotected immersion in temperatures below 10°C (50°F) causes quickly maximum intensity cold shock with hyperventilation.

How many hours of daylight does Longyearbyen have in September?

In September, the average length of the day in Longyearbyen, Svalbard and Jan Mayen, is 14.4h.

How long on average sun shines in September in Longyearbyen?

The average sunshine in September in Longyearbyen is 2.5h.

How high is the UV index in September in Longyearbyen?

In Longyearbyen, the average daily maximum UV index in September is 1. A UV Index reading of 2, and below, represents a minimal hazard to health from the exposure to the Sun's UV radiation.
Average rainfall in September - Longyearbyen, Svalbard and Jan Mayen
  • 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 - Longyearbyen, Svalbard and Jan Mayen
  • 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 - Longyearbyen, Svalbard and Jan Mayen
  • 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 - Longyearbyen, Svalbard and Jan Mayen
  • 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 / Average sunshine in September - Longyearbyen, Svalbard and Jan Mayen
  • 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 - Longyearbyen, Svalbard and Jan Mayen
  • 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).