Other facts from our historical weather data: Which is the warmest month in Thornaby on Tees? July has an average maximum temperature of 20°C (68°F) and is the warmest month of the year. Which is the coldest month in Thornaby on Tees? The coldest month is February with an average maximum temperature of 8°C (46°F). Which is the wettest month in Thornaby on Tees? November tops the wettest month list with 74mm (2.9 in) of rainfall. Which is the driest month in Thornaby on Tees? March is the driest month with 53mm (2.1 in) of precipitation. Which is the sunniest month in Thornaby on Tees? May is the sunniest month with an average of 182 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.