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

Lake Summerset

2,342 people, 850 ft above sea level in Winnebago County.

850 ftElevation, city center
2,342People, 2024 estimate
2 sq miLand area
Clear 32°
Clear now Dew point 27° · Calm · high 34°
City of Lake Summerset River Interstate 2 miles
Explore the plate Order a print

The Lake Summerset 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 Lake Summerset

NWS forecast and National Blend of Models · updated 6:00 PM CST
RIGHT NOW Greater Rockford Airport (KRFD) · 6:54 PM
Clear
32° Clear Feels like 32° · high of 34° near 7 PM
WindCalmno gusts
Humidity81%rising to 100% by morning
Pressure30.31 in →steady
Visibility10 mihaze-free
CloudsClear
UV index—no forecast
Dew point 27° · Dry35° by Tuesday: more humid
DryComfortableStickyMuggyOppressive
NEXT RAIN
Showers
Friday30% chance · showers
LIKELY AMOUNT—amounts come within 3 days
LAST RAINNov. 120.01 in · 2 dry days
ALERTS & OUTLOOKS
No watches or warnings for Winnebago County
NWS Chicago and the Storm Prediction Center · checked 7:15 PM
SUN & MOON
↑ 6:47 AM4:36 PM ↓
9 h 49 m of daylight, 2 minutes less than yesterday
Waxing crescent, 27% 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
7p
10p
1a
4a
7a
10a
1p
4p
7p
10p
1a
4a
7a
10a
1p
4p
7p
10p
1a
4a
7a
10a
1p
4p
clear night
clear night
clear night
partly cloudy night
partly cloudy day
mostly sunny
clear day
clear night
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
mostly sunny
mostly sunny
partly cloudy night
mostly clear night
clear night
clear night
mostly clear night
mostly sunny
clear day
clear day
mostly clear night
TEMPERATURE °F
34°
25°
47°
26°
49°
32°
CHANCE OF RAIN
50%
WIND, MPH
0
0
0
0
0
0
0
0
0
0
0
0
2
7
8
7
6
6
6
6
7
9
10
9
HOW IT FEELS · DEW POINT
Dry: dew points 24 to 35°

The next seven days, and how sure we are

Forecast, with the range 8 in 10 ensemble members agree on Normal, about 48° / 31°
SAT Nov. 14 Sunny Sunny
34° 23°
0% rain — WNW 0 A
SUN Nov. 15 Mostly sunny; warmer Mostly sunny; warmer
49° 23°
0% rain — NNW 0 A
MON Nov. 16 Mostly sunny Mostly sunny
52° 29°
0% rain — SW 6 A
TUE Nov. 17 Mostly sunny Mostly sunny
55° 33°
0% rain — S 8 A
WED Nov. 18 Partly cloudy Partly cloudy
56° 43°
10% rain — S 12 B
THU Nov. 19 Partly cloudy Partly cloudy
59° 41°
20% rain — WSW 7 B
FRI Nov. 20 Chance of showers Chance of showers
60° 47°
30% rain up to 0.05″ 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 Lake Summerset about 5,000 feet above the ground was over the open Pacific three days ago, and over the northern Plains a day ago, about 3,190 miles back along its path. It came down from about 14,400 feet up, warming and drying as it sank. Near the ground the air came from British Columbia; at 10,000 feet, from the open Pacific. 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 IN 1959 Nov. 15, 1959

The coldest this week has been

−7° on Nov. 15, 1959, the coldest reading for this week of the year since 1897. Next is −1° in 2019.

−1°
−7°
20191959
Source: NOAA RCC-ACIS, the Brodhead Wwtp record since 1897.
MILE2
THE GROUND

What Lake Summerset stands on

Lake Summerset’s center stands about 850 ft above sea level. Within three miles the land runs from 760 ft to 980 ft, a difference of 220 ft: rolling country.

Under the town center the state geologic map shows Platteville Group (dolostone, limestone), from the Late Ordovician, 454 to 459 million years old.

The section below crosses 4 rock units mapped at the surface.

Lake Summerset, cut in half from northwest to southeast

A section northwest to southeast, 24 miles through the town center
700 ft800 ft900 ft1,000 ft LAKE SUMMERSET850 ftHigh point of the line1,090 ftDurand780 ftPecatonica Riverabout 760 ft ← NWSE →

Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 52×. 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

Galena Group (Trenton Limestone)

Dolostone, limestone. Age: Late Ordovician, 447 to 459 million years old. About 8 mi of the line.

Platteville Group

Dolostone, limestone. Age: Late Ordovician, 454 to 459 million years old. About 8 mi of the line.

Ancell Group

Sandstone, limestone, dolostone. Age: Middle Ordovician to Late Ordovician, 454 to 468 million years old. About 4 mi of the line.

Sinnipee Group

Dolostone. Age: Ordovician, 445 to 487 million years old. About 4 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 Lake Summerset’s rain goes

A raindrop that lands in Lake Summerset reaches the Gulf of America by way of South Branch Otter Creek, Otter Creek, the Sugar, the Pecatonica, the Rock River and the Mississippi: about 1,640 river miles.

THE WAY DOWN, TO SCALE
Lake Summerset≈ 1,640 mi · the Gulf of America
FROM THE CENTER OF LAKE SUMMERSET ≈ 1,640 mi to the Gulf of America South Branch Otter Creek → Otter Creek → Sugar → Pecatonica → Rock River → Mississippi

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

MILE5
THE ALMANAC

Lake Summerset’s year

1991–2020 normals · records since 1897 · Brodhead Wwtp, 11 mi north

Lake Summerset has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 11° in January. A normal year brings about 37 inches of snow; with the rain, that comes to about 38 inches of water.

27°11°32°14°44°25°58°35°70°47°80°57°83°61°81°59°75°50°62°39°46°28°33°17° JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 1234 TODAY 38.3 in rain and snowmelt
Normal high to low, by month Record high to low, by day Rain by month Freezing
July, average83° / 61°high / low, the warmest month
January, average27° / 11°high / low, the coldest month
Rain and melted snow38.3 inwettest months: June and August
Snow a year37.3 insnowiest: January
Hottest on record111°FJuly 14, 1936
Coldest on record−36°FJanuary 30, 1951
Wettest day on record6.65 inAugust 4, 1906
Snowiest day on record14.4 inDecember 9, 2009
90° days a year11none reach 100°
Nights at or below 32°151and 58 days that stay below freezing
Climate typeHot-summer humid continentalKöppen Dfa

AROUND THE RING

1Freeze seasonfrom the first fall freeze, about Oct. 10, to the last in spring, about April 30 (median dates)
2Highs below freezingDec. 16 to Feb. 17; normal highs stay below 32°
3Lows below freezingNov. 4 to April 7; normal lows fall below 32°
4Wettest stretchJune through August: 13.9 of the year’s 38.3 inches
NOVEMBER 14 IN THE RECORD

On November 14 Lake Summerset normally reaches 47° and falls to 28°. The record high is 71°, in 1999; the record low 3°, in 1986. The most rain on this date, 1.25 in, fell in 1899.

MONTH BY MONTH
JanFebMarAprMayJunJulAugSepOctNovDec
Normal high27°32°44°58°70°80°83°81°75°62°46°33°
Normal low11°14°25°35°47°57°61°59°50°39°28°17°
Rain and melt, in1.591.752.113.734.185.564.004.353.782.942.351.96
Snow, inches10.39.34.50.90.10.00.00.00.00.32.29.7
Record high61° (1944)73° (2024)84° (1910)92° (1930)105° (1934)106° (1934)111° (1936)103° (1947)102° (1939)90° (2025)80° (1933)69° (2021)
Record low−36° (1951)−35° (1929)−21° (1962)7° (1982)24° (1978)33° (1945)40° (1965)35° (1915)20° (1899)2° (1925)−18° (1947)−30° (1950)

Normals 1991–2020 and records since 1897 at Brodhead Wwtp, 11 miles north. NOAA, through RCC-ACIS.

MILE7
ON THE NETWORK

Around Lake Summerset on the Forecast Network

Neighboring plates

Rockford IL · 21 MI 21 miles southeast Janesville WI · 25 MI 25 miles northeast Madison WI · 44 MI 44 miles north Aurora IL · 74 MI 74 miles southeast Milwaukee WI · 84 MI 84 miles northeast Chicago IL · 97 MI 97 miles southeast
FORECASTCITY
Map of Lake Summerset, Illinois. Explore the plate
ILLINOIS · WINNEBAGO

Lake Summerset

2,342 people, 850 ft above sea level in Winnebago County.

850 ftElevation
2,342People
2 sq miLand
Clear 32°
ClearDew point 27°
1

Today in Lake Summerset

NEXT 15 HOURS
Now clear night 34° 0%
10p clear night 30° 0%
1a clear night 28° 0%
4a mostly clear night 25° 0%
7a partly cloudy day 25° 0%
10a mostly sunny 39° 0%
Showers
NEXT RAINFriday · 30%
→
Sat0%
Sunny Sunny
23
34
A
Sun0%
Mostly sunny; warmer Mostly sunny; warmer
23
49
A
Mon0%
Mostly sunny Mostly sunny
29
52
A
Tue0%
Mostly sunny Mostly sunny
33
55
A
Wed10%
Partly cloudy Partly cloudy
43
56
B
Thu20%
Partly cloudy Partly cloudy
41
59
B
Fri30%
Chance of showers Chance of showers
47
60
C
Letters show how sure the forecast is: A, models agree; B, some spread; C, check back. Sample data.
THIS WEEK IN 1959 · NOV. 15, 1959

−7°, the coldest this week of the year has been since 1897.

2

What Lake Summerset stands on

Lake Summerset’s center stands about 850 ft above sea level. Within three miles the land runs from 760 ft to 980 ft, a difference of 220 ft: rolling country.

Lake Summerset, northwest to southeast Lake Summerset850 ftPecatonica Riverabout 760 ft ← NWSE → 24 miles through the town center; vertical exaggeration about 100×. Colors: rock at the surface.
Elevation, center850 ft
Within 3 miles760 to 980 ft
Lie of the landRolling (220 ft of relief)
Rock at the surfacePlatteville Group
Its ageLate Ordovician, 454 to 459 million years old
5

Lake Summerset’s year

Lake Summerset has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 11° in January. A normal year brings about 37 inches of snow; with the rain, that comes to about 38 inches of water.

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 1234 38.3 in
July, average83° / 61° · high / low, the warmest month
January, average27° / 11° · high / low, the coldest month
Rain and melted snow38.3 in · wettest months: June and August
Snow a year37.3 in · snowiest: January
Hottest on record111°F · July 14, 1936
Coldest on record−36°F · January 30, 1951
Wettest day on record6.65 in · August 4, 1906
Snowiest day on record14.4 in · December 9, 2009
90° days a year11 · none reach 100°
Nights at or below 32°151 · and 58 days that stay below freezing
Climate typeHot-summer humid continental · Köppen Dfa
1Freeze season · from the first fall freeze, about Oct. 10, to the last in spring, about April 30 (median dates)
2Highs below freezing · Dec. 16 to Feb. 17; normal highs stay below 32°
3Lows below freezing · Nov. 4 to April 7; normal lows fall below 32°
4Wettest stretch · June through August: 13.9 of the year’s 38.3 inches
NOVEMBER 14 IN THE RECORD

On November 14 Lake Summerset normally reaches 47° and falls to 28°. The record high is 71°, in 1999; the record low 3°, in 1986. The most rain on this date, 1.25 in, fell in 1899.

Normals 1991–2020 and records since 1897 at Brodhead Wwtp, 11 miles north. NOAA, through RCC-ACIS.
3

Where the rain goes

≈ 1,640 mito the Gulf of AmericaSouth Branch Otter Creek → Otter Creek → Sugar → Pecatonica → Rock River → Mississippi

A raindrop that lands in Lake Summerset reaches the Gulf of America by way of South Branch Otter Creek, Otter Creek, the Sugar, the Pecatonica, the Rock River and the Mississippi: about 1,640 river miles.