Planning for the weather is a good way to make your trip to Fort Simpson relaxing and enjoyable, especially when you're splurging. The hottest months are usually July and June, with an average temperature of 15°C, while the coldest months are January and December, with an average of -19°C. The snowiest months in Fort Simpson are January, February, December and March, with each month seeing an average of 113 cm of snowfall.