WSVN-TV also reports that the districts have canceled night adult education classes, activities, and athletic programs for Wednesday. Broward County also has canceled all activities and events on Saturday and Sunday.
All Archdiocese of Miami Catholic schools in Miami-Dade and Broward counties also will be closed on Thursday and Friday.
Many other school districts in Florida, Georgia and South Carolina canceled classes on Thursday, and even more announced that they would be closed on Friday.
The hurricane, with sustained winds of more than 115 miles an hour, has been blamed for several deaths in Haiti and elsewhere in the Caribbean region.
Forecasters say the storm could hit Florida — or come dangerously close — late Thursday or early Friday. Authorities were urging hundreds of thousands of people along the lower East Coast to evacuate their homes.
Video from WSVN-TV: