Weather is probably a major factor when you plan your trip to San Jose City, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and May with an average temp of 81°F, while the coldest months are January and February with an average of 77°F. The rainiest months in San Jose City are July, August, September, and June, with each month seeing an average of 16 inches of rainfall.