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 temp of 55°F, while the coldest months are January and February with an average of 26°F. The snowiest months in Trondheim are December, January, November, and February, with each month seeing an average of 8 inches of snowfall.