Other facts from our historical weather data: Which months have the greatest rainfall in Isle of Colonsay? Most rainfall (rainy season) is seen in January, October, November and December. Which is the warmest month in Isle of Colonsay? August has an average maximum temperature of 16°C (61°F) and is the warmest month of the year. Which is the coldest month in Isle of Colonsay? The coldest month is February with an average maximum temperature of 9°C (48°F). Which is the wettest month in Isle of Colonsay? December tops the wettest month list with 183mm (7.2 in) of rainfall. Which is the driest month in Isle of Colonsay? May is the driest month with 84mm (3.3 in) of precipitation. Which is the sunniest month in Isle of Colonsay? 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.