Other facts from our historical weather data: Which is the warmest month in Smithers? 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 Smithers? The coldest month is January with an average maximum temperature of -5°C (23°F). Which is the wettest month in Smithers? October tops the wettest month list with 122mm (4.8 in) of rainfall. Which is the driest month in Smithers? May is the driest month with 62mm (2.4 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.