A fog advisory is in effect for Hamilton and Halton Region with near-zero visibility expected.

Environment Canada says visibility may be significantly and suddenly reduced to near zero Tuesday morning. “If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop,” said the weather agency in a statement on its website.

There is also a risk of freezing drizzle where temperatures have fallen below the freezing mark.

Drivers should be vigilant as untreated surfaces may become slippery.

The conditions are expected to improve through the morning.