Other facts from our historical weather data: Which is the warmest month in Bonar Bridge? 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 Bonar Bridge? The coldest month is December with an average maximum temperature of 7°C (45°F). Which is the wettest month in Bonar Bridge? October tops the wettest month list with 104mm (4.1 in) of rainfall. Which is the driest month in Bonar Bridge? April is the driest month with 82mm (3.2 in) of precipitation. Which is the sunniest month in Bonar Bridge? May is the sunniest month with an average of 178 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.