You might spend a lot of your vacation inside, but if you're planning to venture beyond the casino, looking at local weather trends is a good idea. The hottest months are usually August and July with an average temp of 75°F, while the coldest months are January and February with an average of 47°F. The rainiest months in Izu are July, September, June, and October, with each month seeing an average of 14 inches of rainfall.