Schaumburg Weather in September (1981–2025)

📍 42.04°N, 88.09°W •
📊

September at a Glance in Schaumburg

(1981–2025)
Avg High
🔥
24.3°C
Avg Low
❄️
12.5°C
Avg Temp
🌡️
18.4°C
Avg Rain
🌧️
82 mm
Avg Humidity
💧
72%
Avg Wind
🌬️
2.7 m/s
Avg Solar
☀️
4.3
kWh/m²/day
vs Annual
📈
+9.1°C
temp difference
🌤️Mild afternoons🌤️Cool mornings🌤️Fairly sunny🌧️Wet month🍃Light winds😊Comfortable humidity

Schaumburg September Weather Overview

September is one of the warmer months of the year in Schaumburg, with average highs near 24.3°C and lows around 12.5°C (mean 18.4°C). It is about average for rainfall, averaging 82 mm of rainfall and 72% relative humidity across the period.

Schaumburg September Temperature History (1981–2025)

Range

September is one of the warmer months of the year in Schaumburg. Across 45 years of records, the warmest September in Schaumburg was 2005 — when the month averaged 21.5°C — while the coldest was 1993 at 14.4°C. Typical September days reach 24.3°C with nights near 12.5°C. The long-term trend is warming, about 0.6°C per decade.

1981–1985 vs 2021–2025

Avg Temp17.5°C→20.1°C+2.6°C
Max Temp23.5°C→26.4°C+2.9°C
Min Temp11.4°C→13.8°C+2.4°C

Trend (per decade)

Avg Temp+0.6°C/decade ↗
Max Temp+0.6°C/decade ↗
Min Temp+0.7°C/decade ↗

Distribution of Avg Temp

14.0°C–16.0°C2 yr (4%)
16.0°C–18.0°C16 yr (36%)
18.0°C–20.0°C17 yr (38%)
20.0°C–22.0°C10 yr (22%)

Schaumburg September Rainfall History (1981–2025)

Range

September is about average for rainfall in Schaumburg, averaging 82 mm of rainfall. The wettest September on record was 2008 with 251 mm, while the driest was 2017 at 12 mm.

Schaumburg September Humidity History (1981–2025)

Range

Relative humidity in Schaumburg during September averages 72%. The most humid September was 2019 at 84%, and the least humid was 2024 at 61%.

Schaumburg September Solar History (1981–2025)

Range

September receives about 4.3 kWh/m²/day of solar energy in Schaumburg. The sunniest September was 2004 at 5.2 kWh/m²/day, and the cloudiest was 1986 at 3.2.

Schaumburg September Wind History (1981–2025)

Range

Average wind speed in Schaumburg during September is 2.7 m/s. The windiest September was 1985 at 3.3 m/s, while the calmest was 2025 at 2 m/s.

What September Feels Like in Schaumburg

🌅
Cool
Morning
🌞
Mild
Afternoon
🌆
Cool
Evening
Rain chanceModerate
Outdoor comfort★★★★☆

How September Ranks in Schaumburg

🔥4th warmest month of the year
🌵6th driest month of the year
☀️6th sunniest month of the year

Ranked against the other 11 months using 1981–2025 averages.

Explore Schaumburg Weather by Month

Schaumburg September Averages by Decade

Metric1980s1990s2000s2010s2020sChange
Avg Temp17.6°C17.5°C18.7°C18.8°C19.7°C+2.1°C
Avg High23.5°C23.5°C24.7°C24.3°C25.9°C+2.4°C
Avg Low11.6°C11.6°C12.7°C13.4°C13.5°C+1.9°C
Avg Rain87 mm77 mm89 mm87 mm66 mm-21 mm

Extreme September Records in Schaumburg

🔥Warmest September35.7°C2000
🧊Coldest September-0.2°C1984
🌧️Wettest September251 mm2008
🏜️Driest September12 mm2017
🌬️Windiest September3.3 m/s1985

Key Insights for September

✅

September temperatures in Schaumburg have risen by about 2.6°C between 1981–1985 and 2021–2025.

✅

September has ranged from a record low of -0.2°C (1984) to a record high of 35.7°C (2000).

✅

Rainfall in September is about average for rainfall, averaging 82 mm, with a wettest year of 251 mm.

Is September a Good Time to Visit Schaumburg?

One of the best times to visit Schaumburg

September is one of the best times to visit Schaumburg. Expect days averaging 24.3°C and nights around 12.5°C (mean 18.4°C) — warmer than Schaumburg's yearly average — with higher rainfall (82 mm), so conditions are generally comfortable for sightseeing and outdoor plans.

See Schaumburg's complete weather history All 12 months side by side, 1981–2025 records, annual trends and long-term averages in one place. View full history →

Schaumburg Weather in September — In Depth

☀️ September climate overview

September is one of the warmer months of the year in Schaumburg, with average highs near 24.3°C and lows around 12.5°C (mean 18.4°C). It is about average for rainfall, averaging 82 mm of rainfall and 72% relative humidity across the period.

🌧️ Rain, humidity & wind in September

September averages 82 mm of rainfall in Schaumburg, about average for rainfall compared with the rest of the year. The wettest September on record saw 251 mm (2008), and the driest just 12 mm (2017). Humidity sits around 72% and average wind speed is 2.7 m/s, with solar radiation averaging 4.3 kWh/m²/day.

📈 How September has changed

Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.6°C. Daytime highs moved from 23.5°C to 26.4°C and overnight lows from 11.4°C to 13.8°C over the same span.
September Weather in Schaumburg, Year by Year
🔥 warmest❄️ coldest🌧️ wettest
YearAvg HighAvg TempAvg LowHottest DayColdest DayRainfallHumidityWindSolar
202526.9°C20.3°C13.7°C31.6°C6.4°C35 mm66%2 m/s4.8
202427.5°C20.8°C14.0°C32.7°C7.4°C41 mm61%2.4 m/s4.9
202325.6°C19.9°C14.2°C34.8°C9.2°C100 mm72%2.3 m/s3.9
202224.8°C18.8°C12.9°C32.4°C4.6°C83 mm72%2.5 m/s4.4
202127.3°C20.7°C14.1°C32.4°C7.2°C32 mm66%2.9 m/s4.6
202023.1°C17.5°C11.9°C30.9°C6.1°C102 mm76%3.1 m/s3.7
201924.8°C20.1°C15.3°C29.1°C10.5°C224 mm84%2.7 m/s3.6
201824.5°C19.3°C14.2°C31.6°C2.6°C105 mm79%2.5 m/s4.1
201726.7°C20.2°C13.7°C34.5°C7.8°C12 mm66%2.5 m/s4.9
201625.0°C20.2°C15.3°C32.0°C8.8°C65 mm79%3 m/s4.2
201525.5°C20.1°C14.8°C33.3°C7.2°C112 mm77%2.6 m/s4.5
201422.7°C16.9°C11.1°C29.0°C4.1°C78 mm78%2.4 m/s4.4
201325.2°C19.1°C13.0°C34.9°C6.8°C58 mm73%2.7 m/s4.7
201223.8°C17.7°C11.6°C32.5°C2.7°C48 mm68%2.8 m/s4.7
201121.6°C16.8°C11.9°C34.3°C3.6°C99 mm74%2.9 m/s4.1
201023.3°C17.9°C12.6°C30.2°C8.2°C69 mm75%3.2 m/s4.2
200923.8°C18.4°C13.0°C28.7°C5.6°C29 mm77%2.2 m/s4.5
2008 🌧️23.6°C18.4°C13.3°C34.8°C7.5°C251 mm81%2.4 m/s3.9
200725.1°C18.8°C12.5°C30.8°C2.3°C37 mm74%2.9 m/s4.9
200621.8°C16.6°C11.3°C28.4°C4.2°C116 mm78%2.8 m/s3.7
2005 🔥27.9°C21.5°C15.1°C34.3°C4.5°C65 mm65%2.9 m/s4.4
200426.5°C19.9°C13.4°C30.4°C8.2°C15 mm67%2.6 m/s5.2
200324.4°C18.0°C11.7°C31.7°C3.2°C51 mm66%2.9 m/s4.5
200226.9°C20.2°C13.4°C33.8°C4.4°C65 mm67%2.4 m/s4.7
200122.4°C16.7°C11.0°C31.1°C2.5°C138 mm76%2.8 m/s4.3
200024.1°C18.1°C12.1°C35.7°C3.5°C127 mm69%3.2 m/s4.1
199925.0°C18.0°C10.9°C34.1°C3.9°C89 mm62%2.9 m/s4.7
199826.6°C20.2°C13.8°C33.3°C9.7°C72 mm69%2.5 m/s4.6
199724.3°C18.2°C12.0°C31.0°C6.9°C59 mm71%2.7 m/s4.2
199623.0°C17.4°C11.8°C30.1°C6.0°C68 mm73%2.5 m/s4.2
199522.8°C16.6°C10.4°C31.1°C1.8°C41 mm66%2.8 m/s4.3
199424.3°C18.5°C12.6°C31.8°C5.5°C48 mm73%2.4 m/s4
1993 ❄️19.2°C14.4°C9.7°C24.7°C0.5°C126 mm81%2.9 m/s3.3
199222.0°C16.2°C10.5°C27.8°C0.7°C148 mm77%2.9 m/s3.8
199123.4°C17.3°C11.2°C32.6°C0.4°C77 mm67%2.7 m/s4.3
199024.2°C18.4°C12.6°C32.7°C3.5°C39 mm73%2.8 m/s4.3
198921.5°C15.9°C10.4°C28.3°C2.0°C76 mm76%2.5 m/s4.4
198826.2°C19.1°C12.0°C31.7°C5.8°C61 mm63%3 m/s4.1
198722.4°C17.2°C11.9°C28.0°C6.4°C58 mm79%2.4 m/s3.9
198624.0°C18.7°C13.3°C28.4°C5.7°C215 mm76%2.9 m/s3.2
198524.0°C18.4°C12.8°C33.5°C3.7°C63 mm70%3.3 m/s3.6
198423.5°C17.0°C10.4°C33.3°C-0.2°C83 mm67%3 m/s4
198324.4°C17.9°C11.4°C33.2°C2.1°C104 mm68%2.9 m/s—
198223.6°C17.5°C11.3°C30.0°C3.8°C41 mm73%2.8 m/s—
198122.1°C16.5°C10.9°C28.0°C2.6°C82 mm76%2.9 m/s—

Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.

Other Cities in Illinois

Schaumburg September Weather — FAQ

What is the average temperature in Schaumburg in September?▼

The average high in September is around 24.3°C with lows near 12.5°C (mean 18.4°C), based on 45 years of NASA POWER data.

Does it rain a lot in Schaumburg in September?▼

September averages 82 mm of rainfall in Schaumburg, about average for rainfall. The wettest on record was 251 mm in 2008.

What was the hottest September on record in Schaumburg?▼

The hottest September reached 35.7°C in 2000. The coldest dipped to -0.2°C in 1984.

Has September in Schaumburg gotten warmer over time?▼

Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.6°C. Daytime highs moved from 23.5°C to 26.4°C and overnight lows from 11.4°C to 13.8°C over the same span.

Is September a good time to visit Schaumburg?▼

September is one of the warmer months of the year in Schaumburg and about average for rainfall, so plan for around 24.3°C daytime highs and 12.5°C at night.

Is September the coldest month in Schaumburg?▼

Not quite — September is the 9th coolest month in Schaumburg, averaging 18.4°C.

What should I pack for Schaumburg in September?▼

For September in Schaumburg, pack light layers you can adjust through the day, with typical highs of 24.3°C and lows of 12.5°C. Bring an umbrella or light rain jacket too.

Is Schaumburg humid in September?▼

Relative humidity in September averages 72% — moderately humid.

How windy is Schaumburg in September?▼

Average wind speed in September is 2.7 m/s. The windiest September on record averaged 3.3 m/s (1985).

Which September had the most rainfall in Schaumburg?▼

The wettest September on record was 2008 with 251 mm. On average, September sees 82 mm.

Where does this September weather data come from?▼

All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.

Other Illinois cities

Explore how the weather in Schaumburg behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.