A winter weather advisory issued by the National Weather Service on Friday warns of freezing rain and ice accumulations up to two-tenths of an inch.
The advisory is in effect from midnight Friday through 9 a.m. Saturday and applies to Winnebago, Boone, McHenry and Ogle counties.
Periods of freezing rain are expected to cause travel difficulties. Drivers should expect slippery roads and slow down while driving, according to the service.
Temperatures are expected to rise above freezing Saturday morning, according to the service. There is a chance of light snow overnight Saturday into Sunday in McHenry County.