Other facts from our historical weather data: Which is the warmest month in Cairndow? 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 Cairndow? The coldest month is February with an average maximum temperature of 7°C (45°F). Which is the wettest month in Cairndow? January tops the wettest month list with 220mm (8.7 in) of rainfall. Which is the driest month in Cairndow? May is the driest month with 122mm (4.8 in) of precipitation. Which is the sunniest month in Cairndow? May is the sunniest month with an average of 189 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.