Crystal Lake in Fall
In fall (September, October and November), Crystal Lake sees average daytime highs around 60°F and overnight lows near 44°F, with 8.3 in of precipitation over about 25 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 78°F in early September to 41°F by late November. The sky is clear or mostly clear about 33% of the time across fall, and the air most often feels dry.
Fall is Crystal Lake's 2nd-best season to visit on our travel score. For the whole year in context, see Crystal Lake's year-round climate.
- Avg daytime high
- 60°F
- 2nd-warmest season
- Avg overnight low
- 44°F
- Precipitation
- 8.3 in
- 25 wet days
- Avg wind
- 8 mph
- Travel score
- 4.5
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Crystal Lake in Fall
Over the season highs ease from about 78°F in early September to 41°F by late November.
A typical fall day in Crystal Lake reaches about 60°F and drops to 44°F overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Crystal Lake
Once humidity and wind are folded in, fall brings about 0 days that feel above 90°F and 30 that feel at or below 32°F.
The story in fall is cold — wind chill drags the overnight "feels like" below the raw low.
Crystal Lake weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 30° / 17° | 2.0 | 7.9 | 6 | 9.3 | 0.0 |
| Feb | 34° / 20° | 1.9 | 7 | 5.2 | 10.3 | 0.0 |
| Mar | 45° / 29° | 2.5 | 9.7 | 3.3 | 11.6 | 1.1 |
| Apr | 57° / 39° | 4.3 | 12.3 | 1.1 | 13.1 | 3.7 |
| May | 68° / 50° | 4.3 | 12.2 | 0 | 14.4 | 5.9 |
| Jun | 78° / 61° | 3.8 | 11.8 | 0 | 15 | 6.4 |
| Jul | 82° / 65° | 3.4 | 10.4 | 0 | 14.8 | 6.4 |
| Aug | 80° / 63° | 3.6 | 10.6 | 0 | 13.7 | 6.6 |
| Sep | 73° / 55° | 3.0 | 8.8 | 0 | 12.3 | 7.0 |
| Oct | 60° / 44° | 3.0 | 8.7 | 0.2 | 10.8 | 5.0 |
| Nov | 46° / 33° | 2.4 | 7.8 | 1.6 | 9.6 | 1.4 |
| Dec | 35° / 22° | 2.1 | 8 | 4.6 | 9 | 0.0 |
Cloud cover in Fall
The sky is clear or mostly clear about 33% of the time across fall.
Chance of precipitation in Fall
Crystal Lake gets around 8.3 in of rain and snow over 25 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 8 mph across fall.
Sunrise & sunset in Fall
Daylight runs from about 13 hours in early September to 9 h 12 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 3.1 kWh/m².
Is fall a good time to visit Crystal Lake?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a reasonable time to visit Crystal Lake for sightseeing.
What to pack for Crystal Lake in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Crystal Lake sees daytime highs around 60°F and nights near 44°F. Pack a warm layer. Worth having: light clothes, a heavy coat and rain gear. About 25 days see rain.
Sea temperature near Crystal Lake in Fall
The nearest coast averages about 57°F across fall — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 24 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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 38 | 36 | 36 | 38 | 43 | 55 | 68 | 71 | 67 | 57 | 47 | 42 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Refreshing | Refreshing | Cool | Bracing | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 38 | Bracing |
| Feb | 36 | Bracing |
| Mar | 36 | Bracing |
| Apr | 38 | Bracing |
| May | 43 | Bracing |
| Jun | 55 | Bracing |
| Jul | 68 | Refreshing |
| Aug | 71 | Refreshing |
| Sep | 67 | Cool |
| Oct | 57 | Bracing |
| Nov | 47 | Bracing |
| Dec | 42 | Bracing |
UV index in Crystal Lake in Fall
Clear-sky midday UV across fall averages around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Crystal Lake 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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 2 | 4 | 6 | 8 | 9 | 8 | 8 | 6 | 3 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | Very high | Very high | Very high | Very high | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 2 | Moderate |
| Mar | 4 | Moderate |
| Apr | 6 | High |
| May | 8 | Very high |
| Jun | 9 | Very high |
| Jul | 8 | Very high |
| Aug | 8 | Very high |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Moderate |
| Dec | 1 | Low |
Air quality in Crystal Lake in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.
Air quality in Crystal Lake 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).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 12 | 15 | 16 | 14 | 15 | 16 | 17 | 16 | 13 | 9 | 10 | 11 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 12 | Moderate |
| Feb | 15 | Moderate |
| Mar | 16 | Moderate |
| Apr | 14 | Moderate |
| May | 15 | Moderate |
| Jun | 16 | Moderate |
| Jul | 17 | Moderate |
| Aug | 16 | Moderate |
| Sep | 13 | Moderate |
| Oct | 9 | Good |
| Nov | 10 | Good |
| Dec | 11 | Good |
Where is Crystal Lake?
Crystal Lake sits at 42.2°N, 88.3°W, 915 ft above sea level, in United States. The nearest listed city is Lake in the Hills, 4.3 mi away.
Topography around Crystal Lake
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Crystal Lake.
Within 2 miles, the terrain around Crystal Lake has only modest variations in elevation — a maximum elevation change of 171 ft around an average of 906 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 322 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 787 ft.
The land around Crystal Lake is covered by trees (47%) and artificial surfaces (27%) within 2 miles, trees (39%) and grassland (26%) within 10 miles, and cropland (38%) and trees (21%) within 50 miles.
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
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 Crystal Lake (42.2411°, -88.3162°, elevation 915 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.