Along with the changing leaves, it's another sign winter is just around the corner.

Environment Canada has issued a frost warning for Sunday night covering a big chunk of the GTA.

Included in the warning: Burlington, Durham Region, Markham, Mississauga, Oakville, Pickering, Richmond Hill, Vaughan & northern York Region

Toronto isn't part of the frost warning, though it will be close to freezing Sunday night. The Weather Network is forecasting a low of 3 degrees.