Other facts from our historical weather data: Which is the warmest month in Trearddur? August has an average maximum temperature of 19°C (66°F) and is the warmest month of the year. Which is the coldest month in Trearddur? The coldest month is February with an average maximum temperature of 10°C (50°F). Which is the wettest month in Trearddur? November tops the wettest month list with 126mm (5 in) of rainfall. Which is the driest month in Trearddur? May is the driest month with 66mm (2.6 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.