Monthly Climate
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Best time to visit Chicago

September is the best time to visit Chicago for general sightseeing, with average highs of 23 °C and about 9 wet days. The comfortable season runs roughly May to June.

It depends what you are going for

One month rarely wins on everything. These are the best months on each measure taken on its own.

If you want Best month On that measure
Sightseeing and walking September comfort 89/100
The least cloud September 48 % average cloud cover
The least rain February 53 mm
Warmth July 28 °C
Cooler weather January -0.2 °C

Ranked by comfort

# Month Comfort / 100 Avg high Wet days
1 September 89 23 °C 9
2 June 80 25 °C 12
3 May 79 20 °C 12
4 August 76 27 °C 11
5 October 73 16 °C 9
6 July 72 28 °C 11
7 April 52 13 °C 12
8 November 42 8.8 °C 9
9 February 29 1.5 °C 7
10 March 28 6.6 °C 10
11 January 26 -0.2 °C 9
12 December 26 2.6 °C 9

When to think twice

December scores lowest with about 9 wet days and highs near 2.6 °C. That does not make it a bad month — it depends entirely on what you are travelling for. The numbers are all here; the judgement is yours.

The full year

Month Avg high Rainfall Cloud
January -0.2 °C 62 mm 70 %
February 1.5 °C 53 mm 66 %
March 6.6 °C 70 mm 64 %
April 13.0 °C 108 mm 63 %
May 19.5 °C 116 mm 61 %
June 25.3 °C 105 mm 57 %
July 27.9 °C 99 mm 50 %
August 26.9 °C 98 mm 50 %
September 23.2 °C 79 mm 48 %
October 16.4 °C 86 mm 56 %
November 8.8 °C 72 mm 63 %
December 2.6 °C 61 mm 70 %

Data sources and method

Normal period
1991–2020
Dataset version
era5-1991-2020-scores1.1
Last processed

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: comfort score, beach score, season boundaries. Full formulas are on the methodology page.

Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.