Photo: Lara John on Unsplash.com

By Laura Durenberger-Grunow - Boreal Community Media - May 11, 2026


A sure sign of changing seasons, the National Weather Service (NWS) will begin issuing Frost and Freeze Advisory/Warnings for the area beginning Tuesday, May 12, 2026. 

Although the area has been experiencing colder-than-average temperatures, the NWS forecasts a warming trend beginning this week, which will keep overnight lows above the freezing mark for the foreseeable future. 

After May 12, if temperatures are expected to fall at or around 32°F, the NWS will issue a Freeze Watch or Freeze Warning; at 37°F, a Frost Advisory, mainly to help gardeners prepare sensitive vegetation such as annuals, fruit trees, or vegetable seedlings. 

According to the National Weather Service, the average last frost dates in Cook County range from May 21 to May 30.