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Shaded-relief map of Crystal Lake, Illinois: rivers, roads, the city limits and where the water drains.
ILLINOIS · MCHENRY COUNTY

Crystal Lake

41,513 people, 920 ft above sea level in McHenry County.

920 ftElevation, city center
41,513People, 2024 estimate
19 sq miLand area
Sunny 46°
Sunny now Dew point 30° · NNW 13 mph · high 44°
City of Crystal Lake River Interstate 2 miles
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The Crystal Lake plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.

MILE1
TODAY

Today in Crystal Lake

NWS forecast and National Blend of Models · updated 3:00 PM CST
RIGHT NOW Pal-Waukee Airport (KPWK) · 2:52 PM
Sunny
46° Sunny Feels like 40° · high of 44° near 3 PM
WindNNW 13 mphgusts 18
Humidity53%rising to 89% by morning
Pressure30.26 in →steady
Visibility10 mihaze-free
CloudsClear
UV index—no forecast
Dew point 30° · Dryabout the same for three days
DryComfortableStickyMuggyOppressive
NEXT RAIN
Clear
Not this weeknone in the forecast for a week
LIKELY AMOUNT—nothing expected
LAST RAINNov. 110.16 in · 3 dry days
ALERTS & OUTLOOKS
No watches or warnings for McHenry County
NWS Chicago and the Storm Prediction Center · checked 3:45 PM
SUN & MOON
↑ 6:42 AM4:33 PM ↓
9 h 50 m of daylight, 2 minutes less than yesterday
Waxing crescent, 26% lit. Next full moon: Nov. 24.
AIR & POLLEN
18
GOODAir quality index · fine particles
Tomorrow: None, moderate. No pollen source yet.

The next three days, hour by hour

Sky: clear, cloudy, night Rain likely National Blend of Models
SATURDAY, NOV. 14
SUNDAY, NOV. 15
MONDAY, NOV. 16
TUESDAY, NOV. 17
3p
6p
9p
Mid
3a
6a
9a
Noon
3p
6p
9p
Mid
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6a
9a
Noon
3p
6p
9p
Mid
3a
6a
9a
Noon
mostly sunny
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
clear day
clear day
clear day
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
clear day
mostly sunny
mostly sunny
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
mostly sunny
mostly sunny
TEMPERATURE °F
44°
32°
49°
31°
50°
35°
CHANCE OF RAIN
50%
WIND, MPH
8
6
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HOW IT FEELS · DEW POINT
Dry: dew points 28 to 34°

The next seven days, and how sure we are

Forecast, with the range 8 in 10 ensemble members agree on Normal, about 49° / 35°
SAT Nov. 14 Mostly sunny Mostly sunny
44° 32°
0% rain — NNW 8 A
SUN Nov. 15 Sunny; warmer Sunny; warmer
52° 31°
0% rain — NW 1 A
MON Nov. 16 Mostly sunny Mostly sunny
53° 35°
0% rain — SW 7 A
TUE Nov. 17 Mostly sunny Mostly sunny
55° 39°
0% rain — S 9 A
WED Nov. 18 Partly cloudy Partly cloudy
57° 46°
0% rain — S 14 A
THU Nov. 19 Partly cloudy Partly cloudy
61° 46°
10% rain — WSW 10 B
FRI Nov. 20 Partly cloudy Partly cloudy
61° 50°
20% rain — SSE 8 C
How sure are we? AModels agree: highs within 4° BSome spread: within 8° CWide spread: check back
Range from the National Blend of Models percentiles · graded on Forecast Scores
AIR MAIL

Where today’s air came from

The air arriving over Crystal Lake about 5,000 feet above the ground was over the Gulf of Alaska three days ago, and over the northern Plains a day ago, about 2,730 miles back along its path. It came down from about 12,900 feet up, warming and drying as it sank. It feels dry all the same. Traced back 72 hours through NOAA’s hourly RAP analyses and the GFS beyond them, nine paths at each of three heights.

THIS WEEK, FOUR YEARS AGO Nov. 11, 2022

The hottest this week has been

78° on Nov. 11, 2022, the hottest reading for this week of the year since 1948. Next is 74° in 2020.

74°
78°
20202022
Source: NOAA RCC-ACIS, the Mchenry Stratton Lock/Dam record since 1948.
MILE2
THE GROUND

What Crystal Lake stands on

Crystal Lake’s center stands about 920 ft above sea level. Within three miles the land runs from 780 ft to 970 ft, a difference of 190 ft: gently rolling country.

Under the town center the state geologic map shows Silurian System undivided (dolostone, limestone), from the Silurian, 422 to 445 million years old.

The section below crosses 2 rock units mapped at the surface.

Hartland to South Barrington, cut in half

A section northwest to southeast, 24 miles through the town center
700 ft800 ft900 ft CRYSTAL LAKE920 ftWoodstock890 ftCary890 ftBarrington Hills840 ft ← NW · HartlandSouth Barrington · SE →

Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.

Rock at the surface along the line

Silurian System undivided

Dolostone, limestone. Age: Silurian, 422 to 445 million years old. About 18 mi of the line.

Maquoketa Formation or Group

Shale, limestone. Age: Late Ordovician, 445 to 454 million years old. About 6 mi of the line.

From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.

Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.

MILE3
THE WATER

Where Crystal Lake’s rain goes

A raindrop that lands in Crystal Lake reaches the Gulf of America by way of the Crystal Lake Outlet, the Fox River, the Illinois and the Mississippi: about 1,520 river miles.

THE WAY DOWN, TO SCALE
Crystal Lake≈ 1,520 mi · the Gulf of America
FROM THE CENTER OF CRYSTAL LAKE ≈ 1,520 mi to the Gulf of America Crystal Lake Outlet → Fox River → Illinois → Mississippi

Lake on the way: Peoria Lake.

1,190 miles of the trip are on the Mississippi.

Traced down the USGS NHDPlus V2.1 river network from the Census center point of Crystal Lake; river miles along the main stem, rounded.

MILE5
THE ALMANAC

Crystal Lake’s year

1991–2020 normals · records since 1948 · Mchenry Stratton Lock/Dam, 6 mi northeast

Crystal Lake has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 13° in January. A normal year brings about 34 inches of snow; with the rain, that comes to about 37 inches of water.

31°13°35°16°46°26°59°37°70°47°80°57°84°62°82°60°76°51°63°40°48°29°36°19° JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 1234 TODAY CRYSTAL LAKE 37.0 in rain and snowmelt
Normal high to low, by month Record high to low, by day Rain by month Freezing
July, average84° / 62°high / low, the warmest month
January, average31° / 13°high / low, the coldest month
Rain and melted snow37.0 inwettest months: June and May
Snow a year34.5 insnowiest: January
Hottest on record101°FJuly 6, 2012
Coldest on record−32°FJanuary 31, 2019
Wettest day on record4.77 inJuly 15, 1985
Snowiest day on record17.3 inFebruary 2, 2011
90° days a year11very few reach 100°
Nights at or below 32°144and 54 days that stay below freezing
Climate typeHot-summer humid continentalKöppen Dfa

AROUND THE RING

1Freeze seasonfrom the first fall freeze, about Oct. 11, to the last in spring, about April 29 (median dates)
2Highs below freezingDec. 29 to Feb. 8; normal highs stay below 32°
3Lows below freezingNov. 7 to April 4; normal lows fall below 32°
4Wettest stretchMay through July: 13.1 of the year’s 37.0 inches
NOVEMBER 14 IN THE RECORD

On November 14 Crystal Lake normally reaches 49° and falls to 30°. The record high is 70°, in 1999; the record low 10°, in 1996. The most rain on this date, 0.59 in, fell in 2024.

MONTH BY MONTH
JanFebMarAprMayJunJulAugSepOctNovDec
Normal high31°35°46°59°70°80°84°82°76°63°48°36°
Normal low13°16°26°37°47°57°62°60°51°40°29°19°
Rain and melt, in1.651.562.213.634.474.813.803.703.613.212.381.94
Snow, inches11.08.93.91.00.00.00.00.00.00.11.48.2
Record high62° (2008)78° (2024)83° (2012)90° (2002)99° (2018)100° (2022)101° (2012)98° (2024)96° (2017)90° (2026)78° (2022)68° (2001)
Record low−32° (2019)−23° (1996)−13° (2015)14° (2018)26° (2020)35° (2003)44° (2001)40° (2009)28° (1995)22° (2020)4° (2019)−19° (2000)

Normals 1991–2020 and records since 1948 at Mchenry Stratton Lock/Dam, 6 miles northeast, 180 ft lower. NOAA, through RCC-ACIS.

MILE7
ON THE NETWORK

Around Crystal Lake on the Forecast Network

Neighboring plates

Aurora IL · 33 MI 33 miles south Naperville IL · 35 MI 35 miles south Chicago IL · 43 MI 43 miles southeast Milwaukee WI · 60 MI 60 miles north Madison WI · 81 MI 81 miles northwest Fort Wayne IN · 183 MI 183 miles southeast
FORECASTCITY
Map of Crystal Lake, Illinois. Explore the plate
ILLINOIS · MCHENRY

Crystal Lake

41,513 people, 920 ft above sea level in McHenry County.

920 ftElevation
41,513People
19 sq miLand
Sunny 46°
SunnyDew point 30°
1

Today in Crystal Lake

NEXT 15 HOURS
Now mostly sunny 44° 0%
6p mostly clear night 41° 0%
9p mostly clear night 37° 0%
12a mostly clear night 35° 0%
3a mostly clear night 32° 0%
6a mostly clear night 32° 0%
Clear
NEXT RAINNone this week
→
Sat0%
Mostly sunny Mostly sunny
32
44
A
Sun0%
Sunny; warmer Sunny; warmer
31
52
A
Mon0%
Mostly sunny Mostly sunny
35
53
A
Tue0%
Mostly sunny Mostly sunny
39
55
A
Wed0%
Partly cloudy Partly cloudy
46
57
A
Thu10%
Partly cloudy Partly cloudy
46
61
B
Fri20%
Partly cloudy Partly cloudy
50
61
C
Letters show how sure the forecast is: A, models agree; B, some spread; C, check back. Sample data.
THIS WEEK, FOUR YEARS AGO · NOV. 11, 2022

78°, the hottest this week of the year has been since 1948.

2

What Crystal Lake stands on

Crystal Lake’s center stands about 920 ft above sea level. Within three miles the land runs from 780 ft to 970 ft, a difference of 190 ft: gently rolling country.

Crystal Lake, northwest to southeast Crystal Lake920 ft ← NWSE → 24 miles through the town center; vertical exaggeration about 122×. Colors: rock at the surface.
Elevation, center920 ft
Within 3 miles780 to 970 ft
Lie of the landGently rolling (190 ft of relief)
Rock at the surfaceSilurian System undivided
Its ageSilurian, 422 to 445 million years old
5

Crystal Lake’s year

Crystal Lake has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 13° in January. A normal year brings about 34 inches of snow; with the rain, that comes to about 37 inches of water.

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 1234 37.0 in
July, average84° / 62° · high / low, the warmest month
January, average31° / 13° · high / low, the coldest month
Rain and melted snow37.0 in · wettest months: June and May
Snow a year34.5 in · snowiest: January
Hottest on record101°F · July 6, 2012
Coldest on record−32°F · January 31, 2019
Wettest day on record4.77 in · July 15, 1985
Snowiest day on record17.3 in · February 2, 2011
90° days a year11 · very few reach 100°
Nights at or below 32°144 · and 54 days that stay below freezing
Climate typeHot-summer humid continental · Köppen Dfa
1Freeze season · from the first fall freeze, about Oct. 11, to the last in spring, about April 29 (median dates)
2Highs below freezing · Dec. 29 to Feb. 8; normal highs stay below 32°
3Lows below freezing · Nov. 7 to April 4; normal lows fall below 32°
4Wettest stretch · May through July: 13.1 of the year’s 37.0 inches
NOVEMBER 14 IN THE RECORD

On November 14 Crystal Lake normally reaches 49° and falls to 30°. The record high is 70°, in 1999; the record low 10°, in 1996. The most rain on this date, 0.59 in, fell in 2024.

Normals 1991–2020 and records since 1948 at Mchenry Stratton Lock/Dam, 6 miles northeast, 180 ft lower. NOAA, through RCC-ACIS.
3

Where the rain goes

≈ 1,520 mito the Gulf of AmericaCrystal Lake Outlet → Fox River → Illinois → Mississippi

A raindrop that lands in Crystal Lake reaches the Gulf of America by way of the Crystal Lake Outlet, the Fox River, the Illinois and the Mississippi: about 1,520 river miles.

Lake on the way: Peoria Lake.

1,190 miles of the trip are on the Mississippi.