Weather is probably a major factor when you plan your trip to Toyokawa, 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 76°F, while the coldest months are January and February with an average of 44°F. The rainiest months in Toyokawa are July, June, September, and October, with each month seeing an average of 12 inches of rainfall.