Heavy fog has caused school delays and interrupted dozens of flights at Detroit's and Grand Rapids' airports.
The National Weather Service issued advisories for Monday warning people around the state to be cautious because of possible fog. Some delays in the start of school were reported in southeastern Michigan communities near the Monroe area, as well as in some areas of southwestern Michigan.
Read more: Metro Detroit under dense fog advisory
At least 40 flights at Detroit Metropolitan Airport in Romulus have been delayed or cancelled, and flight delays of 20 minutes to two hours have happened at Gerald Ford International Airport in Grand Rapids.
Visibility was less than a quarter mile at times. Misty conditions prevailed around much of the state Monday night.