Other facts from our historical weather data: Which is the warmest month in Kirkby Stephen? July has an average maximum temperature of 18°C (64°F) and is the warmest month of the year. Which is the coldest month in Kirkby Stephen? The coldest month is February with an average maximum temperature of 6°C (43°F). Which is the wettest month in Kirkby Stephen? December tops the wettest month list with 124mm (4.9 in) of rainfall. Which is the driest month in Kirkby Stephen? April is the driest month with 84mm (3.3 in) of precipitation. Which is the sunniest month in Kirkby Stephen? May is the sunniest month with an average of 182 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.