textproduct: Central Illinois

KEY MESSAGES

- Temperatures will drop down into the upper 30s to low 40s tonight. Frost formation may be possible again in south- central and eastern IL. Continue to take precautions to protect sensitive vegetation with these colder temperatures and threat of frost.

- Temperatures will warm this week. Highs tomorrow in the low 70s. By Thursday, temperatures will be back well above normal with highs in the upper 70s, nearing 80, for the end of the week.

DISCUSSION

Issued at 129 PM CDT Sun Oct 18 2026

High pressure is set up over the eastern half of the United States. With the ridging not going anywhere any time soon, clear skies and dry weather will continue across the state for the next week. Winds have picked up to 10-15 mph today but will become very light to near calm again overnight. The main focus of this forecast continues to be the temperatures and maybe additional frost potential tonight.

Temperatures will drop down into the upper 30s to low 40s tonight. Great radiational cooling will be in place again tonight with clear skies and light winds. That mixed with the cold temperatures, frost formation may be possible again in south-central and eastern IL. If radiational cooling overperforms, temperatures could get near freezing in some spots. Continue to take precautions to protect sensitive vegetation with these colder temperatures and threat of frost.

Temperatures have began a warming trend today. Highs tomorrow will be in the low 70s, but by Thursday temperatures will be back well above normal with highs in the upper 70s, nearing 80. Normals for this time of year is around 65-69 degrees across central and southeastern IL.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 609 PM CDT Sun Oct 18 2026

VFR conditions are expected the next 24 hours. Light south winds persist through Monday morning, then back to the east late in the period.

ILX WATCHES/WARNINGS/ADVISORIES

None.