Weather is probably a major factor when you plan your trip to Hamatonbetsu, and keep in mind that cheaper options are usually available when the weather isn't as good. 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.