Other facts from our historical weather data: When is summer in Warrenton?The hottest season / summer takes place in June, July, August and September. Which is the warmest month in Warrenton? July has an average maximum temperature of 31°C (88°F) and is the warmest month of the year. Which is the coldest month in Warrenton? The coldest month is February with an average maximum temperature of 4°C (39°F). Which is the wettest month in Warrenton? April tops the wettest month list with 131mm (5.2 in) of rainfall. Which is the driest month in Warrenton? January is the driest month with 46mm (1.8 in) of precipitation. 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.