Brookfield weather in September

In September, Brookfield sees average daytime highs of 73°F and overnight lows near 58°F, with 3.0 in of rain across 8.8 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 78°F in the first days to 69°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 Brookfield's 1st-clearest and 9th-windiest month. For the whole year in context, see Brookfield's year-round climate.

Daytime high
73°
4th warmest
Overnight low
58°
9th coldest
Rainfall
3.0 in
8.8 wet days
Daylight
12 h 18 min
5:37 AM – 5:54 PM
Cloud cover
50%
1st clearest
Wind
9 mph
9th windiest
Solar energy
4.57 kWh/m²
Travel score
7.0
out of 10

Brookfield is village in Cook County, Illinois United States of America.

Founded
1893

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 78°F in the first days to 69°F by the end.

A typical September day in Brookfield reaches about 73°F in the afternoon and slips back to 58°F overnight — a 15°F spread between the day's warmth and the night's chill. On most days the high lands between 63°F and 83°F. Set against its neighbours, September runs about 6°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17864
27863
37863
47763
57762
67762
77662
87661
97661
107560
117560
127560
137459
147459
157458
167358
177358
187357
197257
207256
217156
227156
237155
247055
257054
266954
276954
286953
296853
306852

How September really feels in Brookfield

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.

Brookfield 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° / 19°2.49.16.19.30.0
Feb34° / 22°2.17.54.810.30.0
Mar44° / 30°2.810.33.111.70.9
Apr56° / 41°4.512.4113.13.5
May67° / 52°4.312.4014.35.8
Jun77° / 63°4.012.10156.4
Jul82° / 67°3.611.6014.76.2
Aug80° / 66°3.810.9013.76.6
Sep73° / 58°3.08.8012.37.0
Oct61° / 47°3.39.50.110.95.1
Nov47° / 35°2.891.29.61.6
Dec36° / 26°2.48.74.290.0

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 15% of September, with mostly cloudy or overcast conditions the remaining 42%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16040
26139
36139
46139
56139
66238
76139
86139
96139
106139
116040
125941
135941
145842
155842
165743
175743
185644
195644
205644
215644
225644
235545
245446
255446
265446
275347
285347
295347
305446

Chance of precipitation in September

Any precipitation

Brookfield gets around 3.0 in of rain over 8.8 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 30% and peaks near 31% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
131
231
331
431
530
630
730
830
930
1030
1130
1230
1330
1430
1530
1630
1730
1830
1930
2030
2130
2230
2330
2430
2530
2630
2730
2830
2930
3029

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 43% of days. Sticky, muggy-or-worse air turns up on roughly 15% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
11625262310
2172626229
3192626218
4202726207
5222725196
6242825186
7262825175
8272824164
9292824154
10312823153
11332823142
12352722142
13372721132
14392721131
15412620121
16432619111
17452518111
18482517101
19512415100
2053241490
2155231390
2257231280
2360221170
2461211170
2563211060
266520960
276719950
286719950
297018840
307117840

Wind in September

Winds average 9 mph in September.

Across September, daily wind ranges from about 8 mph on the calmest days to 9 mph at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light breeze
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
169light breeze
179light breeze
189light breeze
199light breeze
209light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
279light breeze
289light breeze
299light breeze
309light 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 5:21 AM to 5:53 AM, and sunset from 6:21 PM to 5:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:216:21
212.95:236:19
312.95:246:17
412.85:256:16
512.85:266:14
612.85:276:12
712.75:286:10
812.75:296:08
912.65:306:07
1012.65:316:05
1112.55:326:03
1212.55:336:01
1312.45:345:59
1412.45:355:58
1512.35:365:56
1612.35:375:54
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
2711.75:495:34
2811.75:505:32
2911.75:525:31
3011.65:535:29

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 1.61 kWh/m² to a high of 6.55 kWh/m² in June across the year — September's 4.57 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.1Bright
35.1Bright
45.0Bright
55.0Bright
65.0Bright
74.9Bright
84.9Bright
94.8Bright
104.8Bright
114.7Bright
124.7Bright
134.7Bright
144.6Bright
154.6Bright
164.5Bright
174.5Bright
184.4Bright
194.4Bright
204.4Bright
214.3Bright
224.3Bright
234.2Bright
244.2Bright
254.1Bright
264.1Bright
274.0Bright
284.0Moderate
294.0Moderate
303.9Moderate
Planning a trip in September

Is September a good time to visit Brookfield?

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

7.0
Sightseeing
1st-best month of the year
5.3
Beach & pool
4th-best month of the year

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

What to pack for Brookfield in September

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

In September, Brookfield sees daytime highs around 73°F and nights near 58°F. Worth packing: light clothes, rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

Sea temperature near Brookfield 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 12 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 Brookfield 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 Brookfield 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 Brookfield 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 Brookfield 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 Brookfield?

Brookfield sits at 41.8°N, 87.9°W, 623 ft above sea level, in United States. The nearest listed city is La Grange, 1.9 mi away.

Topography around Brookfield

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

Within 2 miles, the terrain around Brookfield has only modest variations in elevation — a maximum elevation change of 269 ft around an average of 633 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 427 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 751 ft.

The land around Brookfield is covered by artificial surfaces (51%) and trees (40%) within 2 miles, artificial surfaces (60%) and trees (29%) within 10 miles, and cropland (28%), water (27%) and trees (20%) within 50 miles.

2 miles
269 ft
10 miles
427 ft
50 miles
751 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: La Grange 1.9 mi · Westchester 2.5 mi · Berwyn 3.7 mi · Maywood 3.7 mi · Bellwood 4.3 mi · Hinsdale 5.0 mi · Cicero 5.0 mi · Melrose Park 5.6 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 Brookfield (41.8239°, -87.8517°, elevation 623 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).