On Thursday at 4:36 a.m. the National Weather Service issued a frost advisory in effect until 9 a.m. for Warren and Morris counties.

Frost advisories are issued from May to October (but can be extended if necessary) when temperatures, winds, and sky cover are favorable for frost development. This is most likely to happen when the temperature is 36 degrees or less. In some cases, the frost is severe enough to end the growing season and is then referred to as a 'killing frost'.

A light freeze is likely outside of Chicago, along with frost developing by Thursday morning. Temps will rebound into the low 60s for Thursday under a mostly sunny sky. Multiple storm systems will approach the area starting Friday, allowing for showers and thunderstorms.

On Thursday at 1:12 a.m. the National Weather Service issued a frost advisory valid for Thursday between 3 a.m. and 9 a.m. for Hunterdon County.

The National Weather Service issued a frost advisory at 9:02 p.m. on Wednesday valid for Thursday between midnight and 10 a.m. for Higher Elevations of Indiana and Beaver County.