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 August and July with an average temp of 61°F, while the coldest months are February and January with an average of 23°F. The snowiest months in Christmas are January, April, November, and March, with each month seeing an average of 23 inches of snowfall.