Fog blanketed parts of Southwestern Ontario Sunday morning.
Environment Canada issued a fog advisory for Perth, Wellington, Oxford, and Eastern Middlesex Counties. By 9 a.m., the advisory ended in all of the areas except for Oxford County.
The weather agency said that there could be near-zero visibility in some areas.
Drivers are warned to slow down, watch for tail lights ahead, and be prepared to stop while the advisory is in effect.