First Frost 2024 Southern Ontario Map. A frost date is the average date of the last light freeze in spring or the first light freeze in fall. Use this mapping tool to find the average of first and last frost date in your city or state by zip code to make sure you start your garden at the right time, not too early, not too late.

This chart provides frost dates across. We expect snow to be near to below normal, except in western ontario (and parts of the prairies)—where it will be above normal.