Other facts from our historical weather data: Which is the warmest month in Dease Lake? July has an average maximum temperature of 17°C (63°F) and is the warmest month of the year. Which is the coldest month in Dease Lake? The coldest month is January with an average maximum temperature of -11°C (12°F). Which is the wettest month in Dease Lake? July tops the wettest month list with 98mm (3.9 in) of rainfall. Which is the driest month in Dease Lake? February is the driest month with 34mm (1.3 in) of precipitation. Which is the sunniest month in Dease Lake? June is the sunniest month with an average of 225 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.