Naperville weather in July

In July, Naperville sees average daytime highs of 83°F and overnight lows near 65°F, with 3.7 in of rain across 11.2 wet days and about 14.7 hours of daylight. It is the 1st-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 83°F through the month. The sky is clear or mostly clear about 34% of the time in July, and the air most often feels muggy.

Daylight stretches from about 15 hours at the start of July to 14 h 18 min by month's end. Set against the rest of the year, July is Naperville's 3rd-clearest and 11th-windiest month. For the whole year in context, see Naperville's year-round climate.

Daytime high
83°
1st warmest
Overnight low
65°
12th coldest
Rainfall
3.7 in
11.2 wet days
Daylight
14 h 48 min
4:36 AM – 7:21 PM
Cloud cover
55%
3rd clearest
Wind
6 mph
11th windiest
Solar energy
6.2 kWh/m²
Travel score
5.9
out of 10

Naperville is city in DuPage and Will counties in Illinois, United States.

Density
1,465/km²
people per km²
Founded
1890

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

Temperature in July

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 83°F through the month.

A typical July day in Naperville reaches about 83°F in the afternoon and slips back to 65°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 75°F and 90°F. Set against its neighbours, July runs about 3°F warmer than June and about 2°F warmer than August.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18264
28264
38264
48264
58265
68265
78365
88365
98365
108365
118365
128365
138365
148365
158365
168365
178366
188366
198366
208366
218365
228365
238365
248365
258365
268365
278265
288265
298265
308265
318265

How July really feels in Naperville

Once humidity and wind are folded in, July 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

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

Naperville weather by month

How July compares with the rest of the year at a glance. July is the 1st-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan31° / 17°2.18.15.99.30.0
Feb35° / 20°2.074.610.30.0
Mar47° / 30°2.79.62.911.71.5
Apr59° / 40°4.411.80.913.14.3
May70° / 51°4.612.7014.36.0
Jun79° / 61°4.311.80156.3
Jul83° / 65°3.711.2014.75.9
Aug81° / 63°3.610.5013.76.5
Sep74° / 55°3.08.3012.37.1
Oct62° / 43°3.19.10.110.95.3
Nov47° / 33°2.58.21.29.61.7
Dec36° / 23°2.284.390.0

Cloud cover in July

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% of the time in July.

Beyond those clear spells, partly cloudy skies cover about 19% of July, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15446
25545
35545
45545
55545
65446
75446
85545
95446
105446
115347
125347
135347
145248
155248
165248
175248
185149
195149
205149
215149
225149
235248
245248
255248
265347
275347
285446
295446
305446
315545

Chance of precipitation in July

Any precipitation

Naperville gets around 3.7 in of rain over 11.2 wet days in July. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 37% and peaks near 38% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
138
237
337
437
537
637
737
837
937
1037
1137
1237
1337
1437
1537
1637
1737
1837
1937
2037
2137
2237
2337
2437
2537
2636
2736
2835
2935
3035
3134

Humidity in July

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, July lands in the muggy band about 29% of days. Sticky, muggy-or-worse air turns up on roughly 45% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
117222227110
217222227120
317222227120
416222227121
516222227121
615212327131
715212328131
814212328131
913202428131
1013202429141
1112202429141
1211192430151
1311192430151
1410192430161
1510182330162
1610182331162
1710182331172
1810182331172
199182330172
209182330172
219182330172
229192330172
239192330172
249192330172
259202330172
269212329162
279212329152
289222329152
2910222429142
3010232428141
3110232428141

Wind in July

Winds average 6 mph in July.

Across July, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in July

DaylightNight

Daylight runs from about 15 hours at the start of July to 14 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 42 minutes over July. Sunrise moves from 4:26 AM to 4:49 AM, and sunset from 7:26 PM to 7:08 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
115.04:267:26
215.04:267:26
315.04:277:26
415.04:277:26
515.04:287:25
614.94:297:25
714.94:297:25
814.94:307:25
914.94:307:24
1014.94:317:24
1114.94:327:23
1214.84:327:23
1314.84:337:23
1414.84:347:22
1514.84:357:21
1614.84:367:21
1714.74:367:20
1814.74:377:20
1914.74:387:19
2014.74:397:18
2114.64:407:17
2214.64:417:17
2314.64:427:16
2414.54:427:15
2514.54:437:14
2614.54:447:13
2714.44:457:12
2814.44:467:11
2914.44:477:10
3014.44:487:09
3114.34:497:08

Solar energy in July

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in July, about 6.2 kWh/m².

For context, solar energy here swings from a low near 1.65 kWh/m² to a high of 6.3 kWh/m² in June across the year — July's 6.2 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.4Intense
26.4Intense
36.4Intense
46.4Intense
56.4Intense
66.4Intense
76.3Intense
86.3Intense
96.3Intense
106.3Intense
116.3Intense
126.3Intense
136.2Intense
146.2Intense
156.2Intense
166.2Intense
176.2Intense
186.2Intense
196.1Intense
206.1Intense
216.1Intense
226.1Intense
236.1Intense
246.0Intense
256.0Intense
266.0Intense
276.0Intense
286.0Bright
296.0Bright
306.0Bright
315.9Bright
Planning a trip in July

Is July a good time to visit Naperville?

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

5.9
Sightseeing
5th-best month of the year
6.7
Beach & pool
1st-best month of the year

July is a reasonable time to visit Naperville for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Naperville in July

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

In July, Naperville sees daytime highs around 83°F and nights near 65°F. Pack light clothes and sun protection. Worth having: rain gear. About 11 days see rain.

light clothessun protectionrain gear

Sea temperature near Naperville in July

The nearest coast averages about 70°F in July — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 27 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 Naperville in July

LowModerateHighVery highExtreme

Clear-sky midday UV in July peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Naperville 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 Naperville in July

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Naperville is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (October, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodJul 1817 µg/m³Oct 229 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar16Moderate
Apr14Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug16Moderate
Sep13Moderate
Oct9Good
Nov10Good
Dec11Good
Location & terrain

Where is Naperville?

Naperville sits at 41.8°N, 88.1°W, 709 ft above sea level, in United States. The nearest listed city is Lisle, 3.7 mi away.

Topography around Naperville

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

Within 2 miles, the terrain around Naperville has only modest variations in elevation — a maximum elevation change of 161 ft around an average of 728 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 397 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 784 ft.

The land around Naperville is covered by trees (49%) and artificial surfaces (35%) within 2 miles, trees (39%), artificial surfaces (31%) and grassland (22%) within 10 miles, and cropland (42%) within 50 miles.

2 miles
161 ft
10 miles
397 ft
50 miles
784 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
July weather nearby: Lisle 3.7 mi · Woodridge 5.6 mi · Wheaton 6.2 mi · Downers Grove 7.5 mi · Bolingbrook 7.5 mi · West Chicago 7.5 mi · Glen Ellyn 7.5 mi · Carol Stream 8.7 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 Naperville (41.7859°, -88.1473°, elevation 709 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).