You might spend a lot of your vacation inside, 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 49°F, while the coldest months are December and January with an average of 30°F. The rainiest months in Vik I Myrdal are September, February, October, and January, with each month seeing an average of 9 inches of rainfall.