textproduct: Chicago

KEY MESSAGES

- Generally well above normal temperatures will continue, albeit with a modest cool-down on Monday near and north of I-80, and particularly near Lake Michigan.

- There are periodic low/uncertain rain chances in the mid to late workweek period, with the best chance of any meaningful rainfall not until next Saturday (Halloween) night.

DISCUSSION

Issued at 225 PM CDT Sat Oct 24 2026

Tonight through Sunday:

Following a calm, cool, and partly cloudy night tonight (relative to this afternoon's warmth), Sunday has a decent chance to be one of the warmest days of this current stretch. Mid and higher level cloud cover may limit temps from really overperforming, though currently expecting enough sun for widespread mid 70s highs away from the immediate Illinois shore. Localized upper 70s readings are plausible, especially over southwestern sections of the CWA (ie. in/near Pontiac).

Sunday Night through Saturday:

A backdoor cold front will move across the area Sunday night, knocking temps down vs. the weekend for Monday's highs, but still above average for late October. The coolest readings (around 60F/low 60s) will be found near Lake Michigan due to strengthening north-northeast winds. Expansive surface high pressure over the region on Monday night will likely yield the coolest night of the week (still solidly above normal for late October).

Tuesday will warm back to farther above average, followed by another period of well above average temps (highs approaching 80F in spots?!) centered on midweek. Chances for rain mid to late next week, while not zero, are low/nebulous, and the best chance for anything of note looks to be confined to primarily west and north of the local area. If a weakening cold front is able to push south across at least the northern half of the area Thursday-Thursday night, that would result in lower temps than in the official forecast (especially near the lake).

There has been a more consistent signal for a stronger synoptic system or two over the second half of next weekend into the following workweek. First a warm front will lift north Friday- Friday night, giving way to what may shape up to be one of the warmest Halloweens in years. For trick or treating interests, while the official forecast advertises the arrival of low rain chances during the day on Saturday, the ensemble consensus favors late Saturday night into Sunday for widespread rainfall.

Castro

AVIATION /18Z TAFS THROUGH 00Z MONDAY/

Issued at 1236 PM CDT Sat Oct 24 2026

There are no significant aviation weather concerns through the period with SCT to BKN coverage of VFR high clouds expected. Winds remain light (around 5-10 kt) out of the S to SSE this afternoon. They may briefly turn more SE around sunset before gradually returning to SSE overnight and eventually SSW after daybreak Sunday.

Petr

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...None.