Wheaton weather in September

In September, Wheaton sees average daytime highs of 74°F and overnight lows near 56°F, with 2.9 in of rain across 8.3 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 79°F in the first days to 70°F by the end. The sky is clear or mostly clear about 42% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Wheaton's 1st-clearest and 9th-windiest month. For the whole year in context, see Wheaton's year-round climate.

Daytime high
74°
4th warmest
Overnight low
56°
9th coldest
Rainfall
2.9 in
8.3 wet days
Daylight
12 h 18 min
5:38 AM – 5:55 PM
Cloud cover
50%
1st clearest
Wind
7 mph
9th windiest
Solar energy
4.51 kWh/m²
Travel score
7.1
out of 10

Wheaton is city and county seat of DuPage County, Illinois, United States.

Density
1,843/km²
people per km²
Founded
1831

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 79°F in the first days to 70°F by the end.

A typical September day in Wheaton reaches about 74°F in the afternoon and slips back to 56°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 64°F and 85°F. Set against its neighbours, September runs about 6°F cooler than August and about 13°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17961
27961
37961
47860
57860
67860
77759
87759
97758
107658
117658
127657
137557
147556
157556
167456
177455
187455
197354
207354
217254
227253
237253
247152
257152
267051
277051
287051
296950
306950

How September really feels in Wheaton

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Wheaton weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan31° / 18°2.18.35.99.30.0
Feb35° / 21°2.07.14.610.30.0
Mar47° / 30°2.710.12.911.71.4
Apr59° / 40°4.412.2113.14.2
May69° / 51°4.412.7014.35.9
Jun79° / 61°4.212.20156.2
Jul83° / 66°3.711.4014.75.8
Aug81° / 64°3.710.9013.76.5
Sep74° / 56°2.98.3012.37.1
Oct62° / 44°3.19.10.110.95.3
Nov48° / 33°2.58.31.39.61.7
Dec36° / 24°2.284.290.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 42% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 43%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15941
25941
36040
46139
56139
66139
76139
86139
96040
106040
115941
126040
135941
145842
155743
165743
175644
185644
195644
205545
215545
225545
235545
245545
255446
265446
275347
285347
295347
305347

Chance of precipitation in September

Any precipitation

Wheaton gets around 2.9 in of rain over 8.3 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 29% and peaks near 31% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
131
231
330
430
530
630
729
829
929
1029
1129
1229
1329
1429
1529
1629
1728
1828
1928
2028
2128
2227
2327
2428
2528
2628
2728
2828
2928
3027

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 48% of days. Sticky, muggy-or-worse air turns up on roughly 13% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1202525228
2222624217
3232624207
4252724186
5272723175
6292723165
7312722154
8332722153
9352721143
10372621133
11392621132
12412520122
13432519122
14452419111
15472418111
16492317101
17512216101
1853221591
1955211590
2058201480
2160191380
2262191270
2364181170
2466171160
2567171060
267016950
277016950
287215940
297315840
307315840

Wind in September

Winds average 7 mph in September.

Across September, daily wind ranges from about 7 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over September. Sunrise moves from 5:22 AM to 5:54 AM, and sunset from 6:22 PM to 5:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:226:22
212.95:246:20
312.95:256:18
412.85:266:17
512.85:276:15
612.85:286:13
712.75:296:11
812.75:306:09
912.65:316:08
1012.65:326:06
1112.55:336:04
1212.55:346:02
1312.45:356:00
1412.45:365:59
1512.35:375:57
1612.35:385:55
1712.25:405:53
1812.25:415:51
1912.15:425:50
2012.15:435:48
2112.05:445:46
2212.05:455:44
2311.95:465:42
2411.95:475:41
2511.85:485:39
2611.85:495:37
2711.75:505:35
2811.75:515:33
2911.75:535:32
3011.65:545:30

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.51 kWh/m².

For context, solar energy here swings from a low near 1.63 kWh/m² to a high of 6.42 kWh/m² in June across the year — September's 4.51 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.1Bright
25.0Bright
35.0Bright
45.0Bright
54.9Bright
64.9Bright
74.8Bright
84.8Bright
94.8Bright
104.7Bright
114.7Bright
124.6Bright
134.6Bright
144.6Bright
154.5Bright
164.5Bright
174.4Bright
184.4Bright
194.3Bright
204.3Bright
214.3Bright
224.2Bright
234.2Bright
244.1Bright
254.1Bright
264.0Bright
274.0Moderate
284.0Moderate
293.9Moderate
303.9Moderate
Planning a trip in September

Is September a good time to visit Wheaton?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.1
Sightseeing
1st-best month of the year
5.6
Beach & pool
4th-best month of the year

September is one of the better times to visit Wheaton for general sightseeing.

What to pack for Wheaton in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Wheaton sees daytime highs around 74°F and nights near 56°F. Worth packing: light clothes, rain gear and sun protection. About 8 days see rain.

light clothesrain gearsun protection

Sea temperature near Wheaton in September

The nearest coast averages about 68°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 25 mi away) is warmest in August at about 73°F and coldest in February near 36°F.

It's comfortable for a long swim from Jul 13 to Sep 15 — about 2.1 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb36Bracing
Mar36Bracing
Apr39Bracing
May45Bracing
Jun57Bracing
Jul70Refreshing
Aug73Refreshing
Sep68Refreshing
Oct58Bracing
Nov49Bracing
Dec42Bracing

UV index in Wheaton in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Wheaton peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 23UV 9Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Wheaton in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Wheaton is worst in July — around 21 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 10 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodJul 921 µg/m³Oct 2410 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar18Moderate
Apr19Moderate
May20Moderate
Jun21Moderate
Jul21Moderate
Aug18Moderate
Sep15Moderate
Oct10Good
Nov10Good
Dec11Good
Location & terrain

Where is Wheaton?

Wheaton sits at 41.9°N, 88.1°W, 758 ft above sea level, in United States. The nearest listed city is Glen Ellyn, 2.5 mi away.

Topography around Wheaton

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Wheaton.

Within 2 miles, the terrain around Wheaton has only modest variations in elevation — a maximum elevation change of 115 ft around an average of 764 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 390 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 892 ft.

The land around Wheaton is covered by trees (53%) and artificial surfaces (32%) within 2 miles, trees (41%), artificial surfaces (34%) and grassland (20%) within 10 miles, and cropland (37%) within 50 miles.

2 miles
115 ft
10 miles
390 ft
50 miles
892 ft
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Glen Ellyn 2.5 mi · Carol Stream 3.7 mi · Glendale Heights 3.7 mi · Lisle 5.0 mi · West Chicago 5.0 mi · Lombard 5.0 mi · Naperville 6.2 mi · Villa Park 6.2 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Wheaton (41.8661°, -88.107°, elevation 758 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).