If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Longyearbyen: 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.