What September feels like in Chicago
September is early autumn in Chicago. Daytime temperatures are mild — neither cold nor hot for walking around. There is little difference between day and night: nights stay mild, and evenings feel much like the afternoon. The air is fairly humid, though at these temperatures it rarely feels oppressive.
Rain in Chicago in September
It is a changeable month: rain comes about one day in 3, with dry spells in between. When rain comes it is heavy, about 9.9 mm (0.4 in) per wet day, often in short, strong bursts. The yearly figure is similar, around 8.5 mm per wet day.
Daylight and sunshine in September
In mid-September, sunrise is at about 6:29 am and sunset at about 7:02 pm (local time) — 12 h 33 min of daylight. Evenings are drawing in — 1 h 22 min less daylight than mid-August. The sun is out for roughly 79% of those daylight hours, so there are plenty of bright spells.
How September compares to the rest of the year
September is the 4th warmest month of the year in Chicago. Afternoons run 3.5°C (6.3°F) cooler than in August, with 10 mm less rain. Temperatures keep falling into October. The next month's average high: 15.8°C (60.4°F).
Who September suits
- Sightseeing: a good fit — daytime temperatures are fine for walking around.
- Parks & outdoor: a good fit — pleasant for gardens, parks and riversides.
- Beach: less ideal — too many rainy days.
Tips for visiting Chicago in September
Rain Protection
A compact umbrella and a light waterproof jacket.
Sunglasses
Bright days make sunglasses worth packing.
Quick questions
How warm is Chicago in September?
Afternoons average 22.6°C (72.7°F) and nights about 16.1°C (61°F) — mild by most people's standards. It is the 4th warmest month of the year.
Does it rain a lot in Chicago in September?
Quite a lot — 89 mm spread over about 9 days.
What should I wear in Chicago in September?
Pack rain protection and sunglasses. There is little need to change for the evening.
Is September or October better for visiting Chicago?
September scores better on our climate ranking (#1 of 12 vs #6), rated Great against Good. October is cooler and has more rainy days.