McHenry weather in October

In October, McHenry sees average daytime highs of 60°F and overnight lows near 44°F, with 3.0 in of precipitation across 8.7 wet days and about 10.8 hours of daylight. It is the 6th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 66°F in the first days to 54°F by the end. The sky is clear or mostly clear about 32% of the time in October, and the air most often feels dry.

Daylight stretches from about 11 h 30 min at the start of October to 10 h 12 min by month's end. Set against the rest of the year, October is McHenry's 4th-clearest and 5th-windiest month. For the whole year in context, see McHenry's year-round climate.

Daytime high
60°
6th warmest
Overnight low
44°
7th coldest
Precipitation
3.0 in
8.7 wet days
Daylight
10 h 48 min
6:13 AM – 5:03 PM
Cloud cover
59%
4th clearest
Wind
9 mph
5th windiest
Solar energy
3.01 kWh/m²
Travel score
5.0
out of 10

McHenry is city in Illinois, United States.

Density
684/km²
people per km²
Founded
1872

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

Temperature in October

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 66°F in the first days to 54°F by the end.

A typical October day in McHenry reaches about 60°F in the afternoon and slips back to 44°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 48°F and 73°F. Set against its neighbours, October runs about 13°F cooler than September and about 14°F warmer than November.

20°40°60°80°151015202531
Avg high (°F)Avg low (°F)
16749
26749
36648
46648
56548
66547
76547
86446
96446
106346
116345
126245
136245
146144
156144
166044
176043
185943
195943
205842
215842
225842
235741
245641
255641
265640
275540
285540
295439
305439
315338

How October really feels in McHenry

Once humidity and wind are folded in, October 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

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

McHenry weather by month

How October compares with the rest of the year at a glance. October is the 6th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan30° / 17°2.07.969.30.0
Feb34° / 20°1.975.210.30.0
Mar45° / 29°2.59.73.311.61.1
Apr57° / 39°4.312.31.113.13.7
May68° / 50°4.312.2014.45.9
Jun78° / 61°3.811.80156.4
Jul82° / 65°3.410.4014.86.4
Aug80° / 63°3.610.6013.76.6
Sep73° / 55°3.08.8012.37.0
Oct60° / 44°3.08.70.210.85.0
Nov46° / 33°2.47.81.69.61.4
Dec35° / 22°2.184.690.0

Cloud cover in October

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 32% of the time in October.

Beyond those clear spells, partly cloudy skies cover about 14% of October, with mostly cloudy or overcast conditions the remaining 54%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15347
25347
35347
45347
55347
65347
75248
85248
95149
105149
115149
125050
135050
145050
154852
164753
174654
184654
194555
204456
214357
224258
234258
244060
254060
264060
273961
283961
294060
303961
313961

Chance of precipitation in October

Any precipitationSnow

McHenry gets around 3.0 in of rain and snow over 8.7 wet days in October. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 28% and peaks near 29% on the wettest days, and about 0 day brings snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1280
2280
3270
4270
5270
6270
7270
8270
9270
10270
11270
12270
13270
14280
15280
16280
17290
18290
19290
20290
21290
22291
23291
24291
25291
26281
27281
28281
29282
30272
31272

Humidity in October

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, October lands in the dry band about 90% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1781273
2801262
3811162
4811162
5831052
6831052
784952
886941
986941
1087841
1188831
1289731
1389731
1490631
1592620
1692620
1792620
1893520
1993520
2093520
2193520
2293520
2394420
2494420
2594420
2695410
2795410
2895410
2995410
3096310
3196310

Wind in October

Winds average 9 mph in October.

Across October, 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.

051015151015202531
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
168light breeze
178light 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
319light breeze

Sunrise & sunset in October

DaylightNight

Daylight runs from about 11 h 30 min at the start of October to 10 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over October. Sunrise moves from 5:56 AM to 6:32 AM, and sunset from 5:28 PM to 4:41 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.55:565:28
211.55:575:27
311.55:585:25
411.45:595:23
511.46:005:21
611.36:015:20
711.36:035:18
811.26:045:16
911.26:055:15
1011.16:065:13
1111.16:075:11
1211.06:085:10
1311.06:105:08
1410.96:115:06
1510.96:125:05
1610.86:135:03
1710.86:145:01
1810.76:165:00
1910.76:174:58
2010.66:184:57
2110.66:194:55
2210.66:214:54
2310.56:224:52
2410.56:234:51
2510.46:244:49
2610.46:254:48
2710.36:274:47
2810.36:284:45
2910.26:294:44
3010.26:314:43
3110.26:324:41

Solar energy in October

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in October, about 3.01 kWh/m².

For context, solar energy here swings from a low near 1.6 kWh/m² to a high of 6.32 kWh/m² in June across the year — October's 3.01 kWh/m² falls in the middle.

01234151015202531
Solar energy (kWh/m²)Level
13.7Moderate
23.7Moderate
33.6Moderate
43.6Moderate
53.5Moderate
63.5Moderate
73.5Moderate
83.4Moderate
93.4Moderate
103.3Moderate
113.3Moderate
123.2Moderate
133.2Moderate
143.1Moderate
153.1Moderate
163.0Moderate
173.0Moderate
182.9Moderate
192.9Moderate
202.9Moderate
212.8Moderate
222.8Moderate
232.7Moderate
242.7Moderate
252.6Moderate
262.6Moderate
272.5Moderate
282.5Moderate
292.5Moderate
302.4Moderate
312.4Moderate
Planning a trip in October

Is October a good time to visit McHenry?

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

5.0
Sightseeing
6th-best month of the year
1.0
Beach & pool
6th-best month of the year

October is a reasonable time to visit McHenry for sightseeing.

What to pack for McHenry in October

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

In October, McHenry sees daytime highs around 60°F and nights near 44°F. Worth packing: a warm layer and rain gear. About 9 days see rain.

a warm layerrain gear

Sea temperature near McHenry in October

The nearest coast averages about 57°F in October — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 21 mi away) is warmest in August at about 71°F and coldest in March near 36°F.

It's comfortable for a long swim from Jul 18 to Sep 8 — about 1.7 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb36Bracing
Mar36Bracing
Apr38Bracing
May43Bracing
Jun55Bracing
Jul68Refreshing
Aug71Refreshing
Sep67Cool
Oct57Bracing
Nov47Bracing
Dec42Bracing

UV index in McHenry in October

LowModerateHighVery highExtreme

Clear-sky midday UV in October peaks around 3 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in McHenry 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 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 21UV 9Dec 21UV 1
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in McHenry in October

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in McHenry 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 McHenry?

McHenry sits at 42.3°N, 88.3°W, 797 ft above sea level, in United States. The nearest listed city is Crystal Lake, 6.8 mi away.

Topography around McHenry

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

Within 2 miles, the terrain around McHenry has only modest variations in elevation — a maximum elevation change of 128 ft around an average of 778 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 312 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 827 ft.

The land around McHenry is covered by trees (38%), artificial surfaces (26%) and grassland (21%) within 2 miles, trees (37%), grassland (27%) and cropland (20%) within 10 miles, and cropland (33%), trees (22%) and water (20%) within 50 miles.

2 miles
128 ft
10 miles
312 ft
50 miles
827 ft
treesgrasslandcroplandartificial surfaceswater
October weather nearby: Crystal Lake 6.8 mi · Cary 8.7 mi · Round Lake 8.7 mi · Woodstock 9.3 mi · Round Lake Beach 9.3 mi · Lake in the Hills 11 mi · Grayslake 12 mi · Algonquin 12 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 McHenry (42.3334°, -88.2668°, elevation 797 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).