Other facts from our historical weather data: Which is the warmest month in St Just? August has an average maximum temperature of 19°C (66°F) and is the warmest month of the year. Which is the coldest month in St Just? The coldest month is February with an average maximum temperature of 11°C (52°F). Which is the wettest month in St Just? November tops the wettest month list with 123mm (4.8 in) of rainfall. Which is the driest month in St Just? June is the driest month with 60mm (2.4 in) of precipitation. Which is the sunniest month in St Just? May is the sunniest month with an average of 220 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.