Longyearbyen weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Poor
Best time to visit: April – June
What is the weather like in Longyearbyen in September?
In September, Longyearbyen is freezing cold: daytime highs average 2 °C, and nights often drop below freezing (−1 °C). The sea averages 3.0 °C – swimming is only for the hardy. The sun is scarce, with only about 3 hours a day. Precipitation, often as snow, falls on about 11 days, totalling 55 mm. Snow falls on about 3 days. All in all, September is not an ideal month for a holiday in Longyearbyen.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 24 | 15 | 18 |
| Day | 6° | 2° | −4° |
| Night | 4° | −1° | −8° |
| Sea | 4° | 3° | 2° |
| Sun | 5 h | 3 h | 0 h |
| Rain days | 11 | 11 | 10 |
More details for September
- Daylight
- 14 h 45 min05:30 – 20:15
- UV index
- 0 · lowclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 13 km/haverage daily peakAll months
- Cloud cover
- 83 %on averageAll months
- Hot days
- 0 days30 °C or more
- Snow days
- 3 days1 cm or more of fresh snowAll months
- Time zone
- UTC+2Arctic/Longyearbyen
How the score comes together
- Temperatureweight 50 %0 %
- Sunshineweight 20 %0 %
- Few rainy daysweight 30 %51 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Warm jacket
- Hat, scarf & gloves
- Rain jacket or umbrella
Longyearbyen in September: quick answers
Is Longyearbyen hot in September?
No. In September, Longyearbyen is freezing cold: daytime highs average 2 °C and nights drop to about −1 °C.
Can you swim in Longyearbyen in September?
Only if you don't mind cold water: in September the sea averages just 3.0 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Longyearbyen in September?
Rain is frequent, with about 11 rainy days and 55 mm in total.
Longyearbyen month by month
The whole year in LongyearbyenAll destinations: SvalbardWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences