Other facts from our historical weather data: Which is the warmest month in San José? April has an average maximum temperature of 26°C (79°F) and is the warmest month of the year. Which is the coldest month in San José? The coldest month is January with an average maximum temperature of 24°C (75°F). Which is the wettest month in San José? October tops the wettest month list with 490mm (19.3 in) of rainfall. Which is the driest month in San José? March is the driest month with 61mm (2.4 in) of precipitation. Which is the sunniest month in San José? March is the sunniest month with an average of 284 hours of sunshine. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.