Driving conditions could be hazardous around the GTA tonight, with heavy fog expected in the region.

Environment Canada issued a fog advisory for Toronto and many surrounding areas Monday night. The advisory covers large parts of York, Durham, Halton and Peel regions, as well as Hamilton.  

Visibility of just 100 to 200 metres is possible in many areas and driving conditions could be hazardous as a result, Environment Canada said.

“Travel is expected to be hazardous due to reduced visibility. If visibility is reduced while driving, turn on your lights and maintain a safe following distance,” the agency said in its advisory.

Porter Airlines said Monday night that all flight activity at Billy Bishop Airport had been suspended due to the heavy fog.

The fog is expected lift either late tonight or early Tuesday morning.

The fog is expected to be followed Tuesday by some unseasonably warm weather. A high of 27 C is in the forecast for Toronto on Tuesday, but it could feel more like 35 with the humidex.

That warm weather is expected to continue on Wednesday, with an expected high pf 26 C before returning to a seasonal high of 19 C on Thursday.