Having a good idea of the weather in Longyearbyen will help you enjoy your stay to the fullest. The hottest months are usually July and August, with an average temperature of 3°C, while the coldest months are March and February, with an average of -12°C. The snowiest months in Longyearbyen are February, November, March and January, with each month seeing an average of 36 cm of snowfall.