Other facts from our historical weather data: Which is the warmest month in Ballyshannon? 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 Ballyshannon? The coldest month is January with an average maximum temperature of 9°C (48°F). Which is the wettest month in Ballyshannon? December tops the wettest month list with 129mm (5.1 in) of rainfall. Which is the driest month in Ballyshannon? April is the driest month with 94mm (3.7 in) of precipitation. 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.