Other facts from our historical weather data: When is the rainy season in Westport? Rainy season in Westport occurs in the months of January, February, March, October, November and December. Which is the warmest month in Westport? 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 Westport? The coldest month is December with an average maximum temperature of 9°C (48°F). Which is the wettest month in Westport? November tops the wettest month list with 312mm (12.3 in) of rainfall. Which is the driest month in Westport? July is the driest month with 24mm (0.9 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.