United States Chicago Weather in September (best month) — Climate Guide
September (best month) in Chicago is Excellent
Chicago Weather in September (best month) — Quick Answer
As of 2026- Avg temp
- 24° / 13°
- Rainfall
- 95mm · 9 days
- Crowds
- Busy
As of 2026, Chicago in September (best month) averages a high of 24°C and low of 13°C with 95mm of rain over about 9 days. Early autumn — high 24°C, low 13°C. T-shirt + light cardigan or jacket. Sunglasses + sunscreen. Light layers for evenings.
September (best month) is Excellent for Chicago.
**September is the sleeper-best Chicago month.** Warm + sunny (24°C) but smaller crowds + hotel rates drop 30% from August. **Chicago Jazz Festival** (Labor Day weekend, free) is the city's premier free jazz event. Cubs season ending; baseball energy high. Wrigleyville pubs lively.
Travel score
Chicago September (best month) Weather Stats
Avg High
24°C
Avg Low
13°C
Rainy Days
9
95mm total
Sunshine
9h
Daily avg
Humidity
67%
Comfortable
UV Index
6
High
Wind
13 km/h
Gusts 28
Sea Temp
20°C
Avg water temp
Crowds
Busy
At attractions
September (best month) Sunrise & Sunset
Air Quality
PM2.5
12 μg/m³
PM10
22 μg/m³
Status
Good
Feels-Like Temperature & Wind
Feels like
Daytime
24°C
Nighttime
13°C
Humidity and wind affect how the actual temperature feels.
Wind
13 km/h
Max gust 28 km/h
Activities Recommended for September (best month)
September (best month) Travel Pros & Cons
Pros
- 24/13°C still warm
- Hotel rates drop 30% from August
- Chicago Jazz Festival (free)
- Smaller crowds
Cons
- Lake water cooling (20°C)
September (best month) Events & Festivals
- Chicago Jazz Festival (Labor Day weekend, Grant Park, free)
- Riot Fest (3rd weekend)
Chicago in September (best month) — Full Picture
**September is the sleeper-best Chicago month.** Warm + sunny (24°C) but smaller crowds + hotel rates drop 30% from August. **Chicago Jazz Festival** (Labor Day weekend, free) is the city's premier free jazz event. Cubs season ending; baseball energy high. Wrigleyville pubs lively.
What to Wear & What to Pack
Early autumn — high 24°C, low 13°C. T-shirt + light cardigan or jacket. Sunglasses + sunscreen. Light layers for evenings.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
13.7°C
3.7°C
11.7/mo
Summer (Jun·Jul·Aug)
27.7°C
17.7°C
10/mo
Autumn (Sep·Oct·Nov)
Current15.7°C
6.7°C
9.7/mo
Winter (Dec·Jan·Feb)
0.3°C
-8°C
9.3/mo
Chicago Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| -1° | -10° | 10d·50mm | 4h | 73% | 1 | Quiet | Low season | |
| 1° | -9° | 9d·45mm | 5h | 71% | 2 | Quiet | Low season | |
| 7° | -3° | 11d·70mm | 6h | 67% | 3 | Quiet | Low season | |
| 14° | 4° | 12d·95mm | 7h | 64% | 5 | Moderate | Shoulder | |
| May (excellent) (Best) | 20° | 10° | 12d·105mm | 9h | 64% | 7 | Moderate | Shoulder |
| June (early summer) (Best) | 26° | 16° | 11d·100mm | 10h | 65% | 8 | Busy | Peak |
| July (peak summer) (Best) | 29° | 19° | 10d·100mm | 10h | 67% | 9 | Very busy | Peak |
| August (Lollapalooza) (Best) | 28° | 18° | 9d·100mm | 9h | 68% | 8 | Very busy | Peak |
| September (best month) (Best) | 24° | 13° | 9d·95mm | 9h | 67% | 6 | Busy | Shoulder |
| 16° | 7° | 10d·80mm | 7h | 67% | 4 | Moderate | Shoulder | |
| 7° | 0° | 10d·70mm | 5h | 73% | 2 | Quiet | Low season | |
| 1° | -5° | 9d·60mm | 4h | 75% | 1 | Busy | Peak |
View Other Months
Chicago September (best month) Hotel Picks
Frequently Asked Questions
Is September (best month) a good time to visit Chicago?
Chicago in September (best month) is Excellent. Tourist crowds are busy and flight/hotel prices are shoulder.
What's the average temperature in Chicago in September (best month)?
Chicago September (best month) averages a high of 24°C and a low of 13°C.
Does it rain much in Chicago in September (best month)?
Chicago September (best month) averages 95mm of rainfall over about 9 rainy days.
What should I wear in Chicago in September (best month)?
Early autumn — high 24°C, low 13°C. T-shirt + light cardigan or jacket. Sunglasses + sunscreen. Light layers for evenings.
What time are sunrise and sunset in Chicago in September (best month)?
Chicago September (best month) sunrise is 06:30 and sunset is 19:00, with 12h 30m of daylight.
What's the air quality like in Chicago in September (best month)?
Chicago September (best month) air quality (AQI) averages 38, rated Good. PM2.5 averages 12μg/m³.
What activities are recommended in Chicago in September (best month)?
In September (best month), Chicago is great for Chicago Jazz Festival (free), Architecture Cruise, Wrigley Field.
Is September (best month) peak season in Chicago?
Chicago September (best month) crowds are busy and prices are shoulder. Advance reservations are strongly recommended.
Best Months to Visit Chicago
View Other Months
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Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.