From the National Weather Service
Freezing conditions expected the next several nights. The abnormally mild weather which has prevailed over the region the last few weeks has resulted in the premature blooming of flowers and trees over southern Illinois. This makes them susceptible to freezing conditions. A hard freeze is expected most of the next several nights, with lows in the lower to mid 20s, beginning tonight.
…FREEZE WARNING REMAINS IN EFFECT FROM 6 PM CST THIS EVENING TO NOON CDT SUNDAY for Effingham, Jasper, Crawford, Clay, Richland and Lawrence counties.
TEMPERATURE…Low temperatures tonight are expected to be in the mid 20s, and Saturday night will be closer to 20. While the Freeze Warning only runs through Sunday morning at this time, similar conditions are likely during the first half of the upcoming week.
IMPACTS…Ornamental and fruit trees and flowers have already started to bloom, and will be very susceptible to a hard freeze.
PRECAUTIONARY/PREPAREDNESS ACTIONS… A Freeze Warning means sub-freezing temperatures are imminent or highly likely. These conditions will kill crops and other sensitive vegetation.