Weather will likely play an important role when you plan your trip to San Pablo, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually June and May with an average temp of 81°F, while the coldest months are January and February with an average of 73°F. The rainiest months in San Pablo are July, August, October, and September, with each month seeing an average of 16 inches of rainfall.