A fog advisory is in effect for York Region and surrounding areas, Environment Canada says.
The dense fog advisory for most of East Central Illinois has been extended until 4 p.m. Sunday.
Visibility could drop to one-quarter mile.
Toronto commuters may feel as though they're driving through Brigadoon early Monday morning - but the fog isn't expected to last.
However, fog patches are expected to continue through today and tonight and into Tuesday morning.
Drivers are cautioned to allow extra time to reach their destinations and keep a safe following distance.
A crash has been reported at Honore Avenue and Fruitville Road in Sarasota County, no roadblock was reported in the area, according to FHP.
Highs will dip back into the 60s for Wednesday and Thursday, but it should be mostly sunny.