You'll likely spend much of your trip indoors, but if you're planning to venture beyond the casino, taking a look at local weather data can help you. The hottest months are usually July and August, with an average temperature of 10°C, while the coldest months are January and February, with an average of -6°C. The snowiest months in Tromsø are February, January, November and December, with each month seeing an average of 58 cm of snowfall.