Planning for the weather is a good way to make your trip to Hamatonbetsu relaxing and enjoyable, especially when you're splurging. The hottest months are usually August and July with an average temp of 61°F, while the coldest months are February and January with an average of 25°F. The snowiest months in Hamatonbetsu are March, January, February, and December, with each month seeing an average of 98 inches of snowfall.