Unseasonable warmth is shaping up across the Midwest, with Illinois and Indiana emerging as a focal point for a rare late-December heat surge heading into 2026. Forecast trends following Christmas indicate temperatures climbing well above seasonal averages during the Dec. 27–Jan. 2 window, putting cities like Chicago at risk of flirting with long-standing warm records.
Climatologically, the final week of December is one of the coldest stretches of the year across the Midwest. Average highs in northern Illinois and northern Indiana typically sit in the low to mid-30s. This year, however, a persistent ridge of high pressure over the central U.S. is expected to funnel milder Pacific air eastward, suppressing Arctic intrusions and allowing daytime highs to surge into the 40s and potentially low 50s at times.
If current trends hold, Chicago could log several consecutive days running 10 to 20 degrees above normal, an anomaly more typical of early spring than the heart of winter. Overnight lows are also forecast to remain elevated, limiting opportunities for snowpack development and accelerating snowmelt where it exists.
Looking beyond New Year’s Day, early outlooks for Jan. 3–16, 2026 suggest the Midwest remains tilted toward above-normal temperatures, though with more variability. Brief cooldowns are possible, but no sustained Arctic pattern is evident at this range. That means winter may start 2026 on a warmer-than-average footing across much of Illinois and Indiana.
While this warm stretch won’t eliminate winter entirely, it does underscore a broader national pattern: the Midwest is firmly embedded in one of the warmest anomalies in the country as 2026 begins. Residents should remain alert for rapid forecast shifts, but for now, winter’s bite appears delayed rather than immediate.
