Superintendant Mark Porter said he made the decision to close schools county-wide because buses may not be safe on the roadways.
The upper Keys may experience Tropical Storm force winds and heavy rains from Thursday into Friday as Hurricane Sandy passes to the east. The Upper Keys are currently under a tropical storm watch with a tropical storm warning issued for adjacent waters in the upper Keys.
Meanwhile, all Archdiocese of Miami schools will be also be closed Friday, the Archdiocese announced Thursday.
The Archdiocese of Miami includes Miami-Dade, Broward and Monroe Counties.
All after-school activities were cancelled on Thursday, including After Care.
For information on public school closings in Miami-Dade, Broward and Monroe Counties, click here.