Other facts from our historical weather data: Which is the warmest month in Irvinestown? July has an average maximum temperature of 19°C (66°F) and is the warmest month of the year. Which is the coldest month in Irvinestown? The coldest month is January with an average maximum temperature of 8°C (46°F). Which is the wettest month in Irvinestown? December tops the wettest month list with 106mm (4.2 in) of rainfall. Which is the driest month in Irvinestown? April is the driest month with 84mm (3.3 in) of precipitation. Which is the sunniest month in Irvinestown? May is the sunniest month with an average of 203 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.