Though weather is just one factor, it can really affect your travel plans, especially if you're planning an extended stay in Montalban. The hottest months are usually March and April with an average temp of 77°F, while the coldest months are January and February with an average of 75°F. The rainiest months in Montalban are July, May, June, and August, with each month seeing an average of 8 inches of rainfall.