Other facts from our historical weather data: When is summer in Martinsburg?The hottest season / summer takes place in June, July, August and September. Which is the warmest month in Martinsburg? 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 Martinsburg? The coldest month is January with an average maximum temperature of 5°C (41°F). Which is the wettest month in Martinsburg? May tops the wettest month list with 113mm (4.4 in) of rainfall. Which is the driest month in Martinsburg? January is the driest month with 61mm (2.4 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.