Other facts from our historical weather data: Which is the warmest month in Long Marton? 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 Long Marton? The coldest month is January with an average maximum temperature of 6°C (43°F). Which is the wettest month in Long Marton? December tops the wettest month list with 122mm (4.8 in) of rainfall. Which is the driest month in Long Marton? April is the driest month with 82mm (3.2 in) of precipitation. Which is the sunniest month in Long Marton? May is the sunniest month with an average of 183 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.