Lockport weather in September

In September, Lockport sees average daytime highs of 75°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 Lockport's 1st-clearest and 9th-windiest month. For the whole year in context, see Lockport's year-round climate.

Daytime high
75°
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
4.54 kWh/m²
Travel score
7.1
out of 10

Lockport is city in Will County, Illinois, United States.

Density
845/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 79°F in the first days to 70°F by the end.

A typical September day in Lockport reaches about 75°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)
18061
27961
37961
47960
57960
67860
77859
87859
97758
107758
117758
127657
137657
147656
157556
167556
177555
187455
197455
207454
217354
227353
237253
247253
257152
267152
277151
287051
297051
307050

How September really feels in Lockport

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.

Lockport 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
Jan32° / 18°2.38.65.59.30.0
Feb36° / 21°2.07.14.610.30.0
Mar47° / 31°2.810.22.811.71.6
Apr60° / 41°4.412.40.713.14.4
May70° / 52°4.612.5014.36.1
Jun80° / 62°4.311.70156.3
Jul83° / 66°3.711.4014.75.7
Aug81° / 64°3.710.2013.76.5
Sep75° / 56°2.98.3012.37.1
Oct62° / 44°3.29.20.110.95.5
Nov48° / 33°2.78.61.29.71.9
Dec37° / 24°2.28.33.890.0

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 (%)
16040
26040
36139
46040
56040
66139
76139
86040
96040
106040
115941
125842
135743
145842
155743
165644
175644
185545
195545
205545
215545
225545
235545
245545
255446
265446
275446
285446
295446
305446

Chance of precipitation in September

Any precipitation

Lockport 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 30% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
130
229
329
429
529
629
729
829
929
1029
1129
1229
1330
1430
1529
1629
1729
1829
1929
2028
2128
2228
2328
2428
2528
2628
2728
2828
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 47% 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 (%)
1192525228
2212625218
3222624207
4242724186
5262823176
6282823165
7302822154
8322822154
9342821143
10362721133
11382720133
12402620122
13422519122
14442518112
15462418111
16482417111
17502316101
18522215101
1955211491
2056211391
2160201280
2262191180
2363191170
2465181070
2566181060
266817960
277016950
287116850
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
217light 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 5:23 AM to 5:53 AM, and sunset from 6:21 PM to 5:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:236:21
212.95:246:20
312.95:256:18
412.85:266:16
512.85:276:14
612.75:286:13
712.75:296:11
812.75:306:09
912.65:316:07
1012.65:326:06
1112.55:336:04
1212.55:346:02
1312.45:356:00
1412.45:365:58
1512.35:375:57
1612.35:385:55
1712.25:395:53
1812.25:405:51
1912.15:415:49
2012.15:435:48
2112.05:445:46
2212.05:455:44
2311.95:465:42
2411.95:475:40
2511.85:485:39
2611.85:495:37
2711.75:505:35
2811.75:515:33
2911.75:525:32
3011.65:535:30

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.54 kWh/m².

For context, solar energy here swings from a low near 1.67 kWh/m² to a high of 6.4 kWh/m² in June across the year — September's 4.54 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
154.5Bright
164.5Bright
174.5Bright
184.4Bright
194.4Bright
204.3Bright
214.3Bright
224.3Bright
234.2Bright
244.2Bright
254.1Bright
264.1Bright
274.0Bright
284.0Moderate
293.9Moderate
303.9Moderate
Planning a trip in September

Is September a good time to visit Lockport?

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
5.8
Beach & pool
4th-best month of the year

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

What to pack for Lockport in September

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

In September, Lockport sees daytime highs around 75°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 Lockport 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 30 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 Lockport 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 Lockport peaks around June 22 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 22UV 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 Lockport 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 Lockport 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 Lockport?

Lockport sits at 41.6°N, 88.1°W, 594 ft above sea level, in United States. The nearest listed city is Crest Hill, 3.1 mi away.

Topography around Lockport

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

Within 2 miles, the terrain around Lockport has only modest variations in elevation — a maximum elevation change of 305 ft around an average of 630 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 Lockport is covered by trees (34%), grassland (31%) and artificial surfaces (24%) within 2 miles, trees (30%), grassland (26%) and artificial surfaces (25%) within 10 miles, and cropland (47%) within 50 miles.

2 miles
305 ft
10 miles
427 ft
50 miles
751 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Crest Hill 3.1 mi · Romeoville 4.3 mi · Joliet 4.3 mi · Homer Glen 6.2 mi · Lemont 6.2 mi · Goodings Grove 6.8 mi · New Lenox 7.5 mi · Bolingbrook 7.5 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 Lockport (41.5895°, -88.0578°, elevation 594 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).