Other facts from our historical weather data: Which is the warmest month in Jamestown ? March has an average maximum temperature of 26°C (79°F) and is the warmest month of the year. Which is the coldest month in Jamestown ? The coldest month is September with an average maximum temperature of 21°C (70°F). Which is the wettest month in Jamestown ? March tops the wettest month list with 17mm (0.7 in) of rainfall. Which is the driest month in Jamestown ? November is the driest month with 9mm (0.4 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.