Other facts from our historical weather data: Which months have the greatest rainfall in McKinleyville? Most rainfall (rainy season) is seen in January, March and December. Does McKinleyville have a dry season? Yes, the months of July and August are very dry. Which is the warmest month in McKinleyville? September has an average maximum temperature of 19°C (66°F) and is the warmest month of the year. Which is the coldest month in McKinleyville? The coldest month is December with an average maximum temperature of 12°C (54°F). Which is the wettest month in McKinleyville? December tops the wettest month list with 237mm (9.3 in) of rainfall. Which is the driest month in McKinleyville? August is the driest month with 4mm (0.2 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.