The National Weather Service issued a Frost Advisory for parts of northwest Indiana Tuesday night as temperatures continue to drop across the Chicago area.
The advisory has been issued until Wednesday at 9 a.m. for the following Indiana counties: Lake, Newton, Benton, Jasper, Porter.
Temperatures are expected to fall into the low-to-mid 30s, resulting in frost formation, according to the National Weather Service.
The frost could kill sensitive outdoor vegetation if left uncovered, officials warned.
The Chicago area has moved into a trend of seeing below-average temperatures ending October after recording unseasonably warm weather for the first several weeks of the month.
Most of the area will likely be partly cloudy Wednesday, though more cloud coverage is expected to sweep through the region leading into Thursday.
The next chance for showers and storms comes Thursday morning, with expected soaking rainfall by the afternoon and evening hours.
The rain is expected to continue during the day Friday, but leave the area by the weekend in time for Halloween festivities.
Trick-or-treating could be cold, but the area should remain dry throughout the day Sunday, according to the latest weather models.