Other facts from our historical weather data: Which is the warmest month in Llanbister? July has an average maximum temperature of 20°C (68°F) and is the warmest month of the year. Which is the coldest month in Llanbister? The coldest month is February with an average maximum temperature of 7°C (45°F). Which is the wettest month in Llanbister? December tops the wettest month list with 100mm (3.9 in) of rainfall. Which is the driest month in Llanbister? September is the driest month with 74mm (2.9 in) of precipitation. Which is the sunniest month in Llanbister? May is the sunniest month with an average of 169 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.