Other facts from our historical weather data: Which is the warmest month in Keswick? July has an average maximum temperature of 19°C (66°F) and is the warmest month of the year. Which is the coldest month in Keswick? The coldest month is February with an average maximum temperature of 7°C (45°F). Which is the wettest month in Keswick? December tops the wettest month list with 145mm (5.7 in) of rainfall. Which is the driest month in Keswick? April is the driest month with 86mm (3.4 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.