When the average temperature hits 7C is the rule I go by. There have been a few articles on this.
Quote:
|
You may be wondering what is the best time to install your winter tires, and for what duration should you have them installed. This primarily depends and your local weather. One thing is for sure, don't wait for the very last minute and have them installed beforehand. A good guideline for installing your winter tires is once the temperature is regularly 7 degrees Celsius or less, and they should be removed once the temperatures are consistently higher than 7 degrees Celsius. This will ensure that they do not wear prematurely in warmer weather, but you shouldn't get caught by surprise.
|
http://www.1010tires.com/store/t-Winter-Tires-CAD.aspx