Weather in Chicago in January

The month to avoid. January is the month most people should skip in Chicago. Highs sit at -0.2 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

January ranks 11 of 12 — near the bottom of Chicago's year. September is the month that works, and the swing between the two is 53 points, which is a different holiday rather than a slightly better one.

Rain on 8 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at -0.2 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 26 nights drop below freezing, so anything left outside stays frozen; the day barely swings — 4.8 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest January day reached 11.9 °C and the coldest night fell to -24.8 °C, and the wettest single day dropped 30 mm — roughly 63% of the month's rain in one day.

January is moderately variable: 14 mm in the driest year against 101 mm in the wettest, around an average of 48 mm. Roughly two Januarys in three land near that average, and the third does something else entirely.

Wind sits around 20.8 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity runs at 86%, which at -0.2 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How January sits in the year

Temperatures hold steady either side: 2.6 °C in December, -0.2 here, 0.3 in February. Nothing about the timing within the month matters much.

Daylight in January

January sits at the dark end of Chicago's year — 9.4 hours of daylight against 15.2 at midsummer, gaining 0.7 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

With no coast nearby, the year swings a fair way — 30.2 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

January in Chicago versus nearby

If Chicago is one option among several, the nearby comparison is worth making. Milwaukee is close enough to be a coin toss — 2.1 °C cooler, 1 day less rain. Grand Rapids is the weaker option in January — within a degree on temperature, 4 days more rain.

So: January is a compromise. September is 53 points better and is what Chicago is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Chicago

See all twelve months in Chicago, or where else to go in January.