Kankakee weather in September

In September, Kankakee sees average daytime highs of 76°F and overnight lows near 56°F, with 3.0 in of rain across 8.1 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 80°F in the first days to 72°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 Kankakee's 1st-clearest and 9th-windiest month. For the whole year in context, see Kankakee's year-round climate.

Daytime high
76°
4th warmest
Overnight low
56°
9th coldest
Rainfall
3.0 in
8.1 wet days
Daylight
12 h 18 min
5:38 AM – 5:54 PM
Cloud cover
49%
1st clearest
Wind
8 mph
9th windiest
Solar energy
4.57 kWh/m²
Travel score
7.1
out of 10

Kankakee is city in Kankakee County, Illinois, United States.

Density
665/km²
people per km²
Founded
1853

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 80°F in the first days to 72°F by the end.

A typical September day in Kankakee reaches about 76°F in the afternoon and slips back to 56°F overnight — a 21°F spread between the day's warmth and the night's chill. On most days the high lands between 66°F and 87°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)
18162
28161
38061
48060
58060
68060
77959
87959
97959
107958
117858
127857
137857
147757
157756
167656
177655
187655
197555
207554
217554
227453
237453
247353
257352
267352
277251
287251
297151
307150

How September really feels in Kankakee

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.

Kankakee weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan33° / 19°2.58.95.39.40.0
Feb38° / 22°2.17.44.210.40.0
Mar49° / 31°3.110.42.211.72.0
Apr62° / 42°4.312.20.613.14.8
May72° / 52°4.513.1014.36.1
Jun80° / 62°4.112.4014.96.0
Jul83° / 66°3.711.2014.75.7
Aug82° / 64°3.49.5013.66.5
Sep76° / 56°3.08.1012.37.1
Oct64° / 45°3.29.10.110.95.8
Nov50° / 34°2.98.61.19.72.3
Dec38° / 25°2.38.23.49.10.0

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 14% of September, with mostly cloudy or overcast conditions the remaining 43%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16040
26040
36040
46040
56040
66040
76040
86040
96040
106040
115941
125941
135842
145743
155743
165644
175644
185644
195545
205545
215446
225446
235446
245446
255347
265347
275347
285248
295347
305347

Chance of precipitation in September

Any precipitation

Kankakee gets around 3.0 in of rain over 8.1 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 28% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
129
229
329
429
529
629
729
829
929
1029
1129
1229
1329
1429
1528
1628
1728
1828
1927
2027
2127
2227
2327
2427
2527
2627
2727
2827
2927
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 14% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1222423247
2232423237
3252522226
4262522216
5282622195
6302621185
7322621174
8342621154
9362620153
10382620143
11392519133
12412519132
13432518122
14452418122
15472417111
16492316111
17502316101
18522215101
1954221491
2057211390
2160201280
2261201180
2363191170
2465181070
2565181070
2667171060
276916960
287115950
297214950
307314940

Wind in September

Winds average 8 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.

051015151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light 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 5:52 AM, and sunset from 6:20 PM to 5:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:226:20
212.95:236:18
312.95:246:17
412.85:256:15
512.85:266:13
612.75:276:11
712.75:286:10
812.65:296:08
912.65:306:06
1012.55:316:04
1112.55:336:03
1212.55:346:01
1312.45:355:59
1412.45:365:57
1512.35:375:56
1612.35:385:54
1712.25:395:52
1812.25:405:50
1912.15:415:49
2012.15:425:47
2112.05:435:45
2212.05:445:43
2311.95:455:41
2411.95:465:40
2511.85:475:38
2611.85:485:36
2711.85:495:34
2811.75:505:33
2911.75:515:31
3011.65:525:29

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.57 kWh/m².

For context, solar energy here swings from a low near 1.7 kWh/m² to a high of 6.33 kWh/m² in June across the year — September's 4.57 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.1Bright
25.1Bright
35.0Bright
45.0Bright
55.0Bright
64.9Bright
74.9Bright
84.8Bright
94.8Bright
104.8Bright
114.7Bright
124.7Bright
134.6Bright
144.6Bright
154.6Bright
164.5Bright
174.5Bright
184.4Bright
194.4Bright
204.4Bright
214.3Bright
224.3Bright
234.2Bright
244.2Bright
254.2Bright
264.1Bright
274.1Bright
284.0Bright
294.0Moderate
303.9Moderate
Planning a trip in September

Is September a good time to visit Kankakee?

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
6.2
Beach & pool
4th-best month of the year

September is one of the better times to visit Kankakee for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Kankakee in September

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

In September, Kankakee sees daytime highs around 76°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 Kankakee 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 43 mi away) is warmest in August at about 73°F and coldest in February near 35°F.

It's comfortable for a long swim from Jul 10 to Sep 16 — about 2.3 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb35Bracing
Mar35Bracing
Apr39Bracing
May46Bracing
Jun59Cool
Jul70Refreshing
Aug73Refreshing
Sep68Refreshing
Oct58Bracing
Nov49Bracing
Dec42Bracing

UV index in Kankakee 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 Kankakee peaks around June 21 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 21UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Kankakee 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 Kankakee is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1418 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar15Moderate
Apr15Moderate
May17Moderate
Jun17Moderate
Jul18Moderate
Aug16Moderate
Sep12Moderate
Oct8Good
Nov9Good
Dec10Good
Location & terrain

Where is Kankakee?

Kankakee sits at 41.1°N, 87.9°W, 656 ft above sea level, in United States. The nearest listed city is Bradley, 1.2 mi away.

Topography around Kankakee

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

Within 2 miles, the terrain around Kankakee has only modest variations in elevation — a maximum elevation change of 121 ft around an average of 633 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 272 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 564 ft.

The land around Kankakee is covered by artificial surfaces (37%) and trees (30%) within 2 miles, cropland (75%) within 10 miles, and cropland (70%) within 50 miles.

2 miles
121 ft
10 miles
272 ft
50 miles
564 ft
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Bradley 1.2 mi · Bourbonnais 2.5 mi · Frankfort 26 mi · Park Forest 27 mi · Matteson 27 mi · New Lenox 27 mi · Mokena 28 mi · Chicago Heights 29 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 Kankakee (41.12°, -87.8611°, elevation 656 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).