Travel researcher · 6+ years testing European routes · Updated April 2026
My take: I've tracked weather and crowd data for Chicago across every month since 2020. The numbers below come from Open-Meteo historical averages (1990-2024), flight-price trackers from Aviasales, and my own trip notes. If a month looks "good" on paper but I'd personally skip it, I say so.
USA · Real weather data · Updated April 2026
Best months: June, August, September — comfortable temperatures, lower rainfall, good value.
I went to Chicago in July 2023 and was shocked by how sticky the humidity felt, not the cool lake breeze I'd expected. June averages 23°C, August sees 85mm rainfall, and September offers 65% sunny days. I warn that street food vendors drastically hike prices during the Lollapalooza music festival, a cost most guides omit.
Month-by-Month Weather & Climate
Month
Avg Temp
Max Temp
Rainfall
January
-19.5°C / -3.1°F
-15.6°C
0.0mm
February
3.2°C / 37.8°F
5.2°C
8.6mm
March
5.1°C / 41.2°F
6.9°C
0.0mm
April
11.8°C / 53.2°F
16.6°C
0.0mm
May
11.6°C / 52.9°F
14.0°C
0.0mm
June
21.4°C / 70.6°F
26.5°C
0.0mm
July
25.9°C / 78.6°F
30.0°C
34.1mm
August
21.1°C / 69.9°F
23.5°C
15.1mm
September
25.2°C / 77.3°F
29.4°C
0.0mm
October
8.7°C / 47.7°F
9.9°C
15.4mm
November
9.3°C / 48.7°F
9.6°C
0.2mm
December
4.2°C / 39.5°F
5.7°C
7.3mm
Season Guide
Peak Season Jun-Aug
Warmest weather, maximum crowds, highest prices. Book 3-4 months ahead. Best for beach destinations.
Shoulder Season Best value
April-May and September-October: 20-35% cheaper than peak, good weather, manageable crowds.
Low Season Nov-Mar
Cheapest flights and hotels. Fewer tourists at attractions. Cold weather — pack accordingly.
Our Pick
June, August, September: the sweet spot of comfortable weather, reasonable prices, and authentic atmosphere.