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Shaded-relief map of Dupo, Illinois: rivers, roads, the city limits and where the water drains.
ILLINOIS · ST. CLAIR COUNTY

Dupo

3,797 people, 410 ft above sea level in St. Clair County.

410 ftElevation, city center
3,797People, 2024 estimate
6 sq miLand area
Sunny 46°
Sunny now Dew point 26° · WNW 3 mph · high 46°
City of Dupo River Interstate 2 miles
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The Dupo 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 Dupo

NWS forecast and National Blend of Models · updated 12:00 PM CST
RIGHT NOW St. Louis Lambert International Airport (KSTL) · 12:51 PM
Sunny
46° Sunny Feels like 45° · high of 46° near 1 PM
WindWNW 3 mphno gusts
Humidity45%falling to 58% this afternoon
Pressure30.32 in →steady
Visibility10 mihaze-free
CloudsClear
UV index—no forecast
Dew point 26° · Dry39° by Tuesday: more humid
DryComfortableStickyMuggyOppressive
NEXT RAIN
Clear
Not this weeknone in the forecast for a week
LIKELY AMOUNT—nothing expected
LAST RAINNov. 40.03 in · 10 dry days
ALERTS & OUTLOOKS
No watches or warnings for St. Clair County
NWS St Louis and the Storm Prediction Center · checked 1:46 PM
SUN & MOON
↑ 6:41 AM4:49 PM ↓
10 h 7 m of daylight, 2 minutes less than yesterday
Waxing crescent, 25% lit. Next full moon: Nov. 24.
AIR & POLLEN
32
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
1p
4p
7p
10p
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1p
4p
7p
10p
1a
4a
7a
10a
clear day
clear night
clear night
clear night
mostly clear night
mostly clear night
partly cloudy day
partly cloudy day
partly cloudy day
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly clear night
clear day
clear day
clear day
clear night
clear night
clear night
clear night
clear night
clear day
clear day
TEMPERATURE °F
46°
31°
50°
33°
52°
36°
CHANCE OF RAIN
50%
WIND, MPH
0
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HOW IT FEELS · DEW POINT
Dry: dew points 28 to 39°

The next seven days, and how sure we are

Forecast, with the range 8 in 10 ensemble members agree on Normal, about 56° / 38°
SAT Nov. 14 Sunny Sunny
46° 30°
0% rain — N 0 A
SUN Nov. 15 Partly cloudy; warmer Partly cloudy; warmer
54° 31°
0% rain — NE 0 A
MON Nov. 16 Sunny Sunny
56° 34°
0% rain — SE 0 A
TUE Nov. 17 Sunny Sunny
59° 37°
0% rain — SE 8 A
WED Nov. 18 Partly cloudy Partly cloudy
63° 47°
0% rain — SSE 14 B
THU Nov. 19 Partly cloudy Partly cloudy
66° 50°
10% rain — SSW 8 C
FRI Nov. 20 Partly cloudy Partly cloudy
68° 52°
10% rain — SE 10 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 Dupo about 5,000 feet above the ground was over the open Pacific three days ago, about 2,760 miles back along its path. It came down from about 12,100 feet up, warming and drying as it sank. Near the ground the air came from the Canadian Prairies; at 10,000 feet, from the northern Rockies. 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 1989 Nov. 11, 1989

The hottest this week has been

85° on Nov. 11, 1989, the hottest reading for this week of the year since 1874. Next is 83° in 2016.

83°
85°
20161989
Source: NOAA RCC-ACIS, the St Louis Area threaded record since 1874.
MILE2
THE GROUND

What Dupo stands on

Dupo’s center stands about 410 ft above sea level. Within three miles the land runs from 390 ft to 670 ft, a difference of 280 ft: rolling country. The highest named summit within 15 miles is Clarks Mound, about 670 ft, 9 miles east-northeast.

Under the town center the state geologic map shows St. Louis Limestone, from the Middle Mississippian, 331 to 347 million years old.

The section below crosses 7 rock units mapped at the surface.

Waterloo to Pagedale, cut in half

A section south to north, 24 miles through the town center
400 ft500 ft600 ft DUPO410 ftHigh point of the line690 ftEast Carondelet410 ftPagedale550 ft ← S · WaterlooPagedale · N →

Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 62×. 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

St. Louis Limestone

Limestone. Age: Middle Mississippian, 331 to 347 million years old. About 11 mi of the line.

Warsaw Formation and Salem Limestone

Limestone. Age: Middle Mississippian, 331 to 347 million years old. About 4 mi of the line.

Marmaton Group

Limestone, shale. Age: Carboniferous, 299 to 324 million years old. About 3 mi of the line.

Cherokee Group - Cabaniss Subgroup, Krebs Subgroup

Shale, sandstone, siltstone. Age: Carboniferous, 299 to 324 million years old. About 3 mi of the line.

Meramecian Series

Limestone. Age: Carboniferous, 324 to 359 million years old. About 3 mi of the line.

Lower Pope Group (Aux Vases Sandstone through Glen Dean Limestone)

Limestone, sandstone, shale. Age: Middle Mississippian, 331 to 347 million years old. About 0.5 mi of the line.

From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit along the line are not listed.

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 Dupo’s rain goes

A raindrop that lands in Dupo reaches the Gulf of America by way of the Mississippi: about 1,150 river miles.

THE WAY DOWN, TO SCALE
Dupo≈ 1,150 mi · the Gulf of America
FROM THE CENTER OF DUPO ≈ 1,150 mi to the Gulf of America Mississippi

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

MILE5
THE ALMANAC

Dupo’s year

1991–2020 normals · records since 1874 · St Louis Lambert International Airport, 18 mi north-northwest

Dupo has a hot-summer humid continental climate. Summer afternoons average 90° in July; winter nights fall to about 24° in January. A normal year brings about 17 inches of snow; with the rain, that comes to about 42 inches of water.

40°24°46°28°57°37°68°47°77°58°86°67°90°71°88°69°81°61°69°49°55°37°45°29° JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 123 TODAY DUPO 41.7 in rain and snowmelt
Normal high to low, by month Record high to low, by day Rain by month Freezing
July, average90° / 71°high / low, the warmest month
January, average40° / 24°high / low, the coldest month
Rain and melted snow41.7 inwettest months: May and April
Snow a year16.6 insnowiest: January
Hottest on record115°FJuly 14, 1954
Coldest on record−22°FJanuary 5, 1884
Wettest day on record8.64 inJuly 26, 2022
Snowiest day on record12.8 inFebruary 26, 1906
90° days a year47about 3 of them 100° or more
Nights at or below 32°85and 19 days that stay below freezing
Climate typeHot-summer humid continentalKöppen Dfa

AROUND THE RING

1Freeze seasonfrom the first fall freeze, about Nov. 2, to the last in spring, about April 2 (median dates)
2Highs of 90° and upJuly 7 to Aug. 4; normal highs reach 90°
3Lows below freezingNov. 30 to March 2; normal lows fall below 32°
NOVEMBER 14 IN THE RECORD

On November 14 Dupo normally reaches 56° and falls to 38°. The record high is 81°, in 1971; the record low 13°, in 1940. The most rain on this date, 1.86 in, fell in 1993.

MONTH BY MONTH
JanFebMarAprMayJunJulAugSepOctNovDec
Normal high40°46°57°68°77°86°90°88°81°69°55°45°
Normal low24°28°37°47°58°67°71°69°61°49°37°29°
Rain and melt, in2.592.233.504.734.824.493.933.382.963.153.422.50
Snow, inches5.74.32.30.20.00.00.00.00.00.00.93.2
Record high77° (1950)86° (2024)93° (2026)93° (2002)98° (1953)108° (2012)115° (1954)110° (1934)104° (2011)94° (2019)86° (1937)78° (2025)
Record low−22° (1884)−18° (1905)−5° (1960)20° (1936)31° (1976)43° (1969)51° (1972)47° (1986)32° (1942)21° (1925)1° (1964)−16° (1989)

Normals 1991–2020 and records since 1874 from the St Louis Area threaded record (St Louis Lambert International Airport, 18 miles north-northwest, 120 ft higher). NOAA, through RCC-ACIS.

MILE7
ON THE NETWORK

Around Dupo on the Forecast Network

Neighboring plates

St. Louis MO · 8 MI 8 miles north O'Fallon MO · 33 MI 33 miles northwest Springfield IL · 93 MI 93 miles north Decatur IL · 115 MI 115 miles northeast Columbia MO · 118 MI 118 miles west Evansville IN · 150 MI 150 miles east
FORECASTCITY
Map of Dupo, Illinois. Explore the plate
ILLINOIS · ST. CLAIR

Dupo

3,797 people, 410 ft above sea level in St. Clair County.

410 ftElevation
3,797People
6 sq miLand
Sunny 46°
SunnyDew point 26°
1

Today in Dupo

NEXT 15 HOURS
Now clear day 46° 0%
4p clear day 45° 0%
7p clear night 40° 0%
10p clear night 36° 0%
1a clear night 33° 0%
4a mostly clear night 32° 0%
Clear
NEXT RAINNone this week
→
Sat0%
Sunny Sunny
30
46
A
Sun0%
Partly cloudy; warmer Partly cloudy; warmer
31
54
A
Mon0%
Sunny Sunny
34
56
A
Tue0%
Sunny Sunny
37
59
A
Wed0%
Partly cloudy Partly cloudy
47
63
B
Thu10%
Partly cloudy Partly cloudy
50
66
C
Fri10%
Partly cloudy Partly cloudy
52
68
C
Letters show how sure the forecast is: A, models agree; B, some spread; C, check back. Sample data.
THIS WEEK IN 1989 · NOV. 11, 1989

85°, the hottest this week of the year has been since 1874.

2

What Dupo stands on

Dupo’s center stands about 410 ft above sea level. Within three miles the land runs from 390 ft to 670 ft, a difference of 280 ft: rolling country. The highest named summit within 15 miles is Clarks Mound, about 670 ft, 9 miles east-northeast.

Dupo, south to north Dupo410 ft ← SN → 24 miles through the town center; vertical exaggeration about 119×. Colors: rock at the surface.
Elevation, center410 ft
Within 3 miles390 to 670 ft
Lie of the landRolling (280 ft of relief)
High point nearbyClarks Mound, 670 ft, 9 mi east-northeast
Rock at the surfaceSt. Louis Limestone
Its ageMiddle Mississippian, 331 to 347 million years old
5

Dupo’s year

Dupo has a hot-summer humid continental climate. Summer afternoons average 90° in July; winter nights fall to about 24° in January. A normal year brings about 17 inches of snow; with the rain, that comes to about 42 inches of water.

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 123 41.7 in
July, average90° / 71° · high / low, the warmest month
January, average40° / 24° · high / low, the coldest month
Rain and melted snow41.7 in · wettest months: May and April
Snow a year16.6 in · snowiest: January
Hottest on record115°F · July 14, 1954
Coldest on record−22°F · January 5, 1884
Wettest day on record8.64 in · July 26, 2022
Snowiest day on record12.8 in · February 26, 1906
90° days a year47 · about 3 of them 100° or more
Nights at or below 32°85 · and 19 days that stay below freezing
Climate typeHot-summer humid continental · Köppen Dfa
1Freeze season · from the first fall freeze, about Nov. 2, to the last in spring, about April 2 (median dates)
2Highs of 90° and up · July 7 to Aug. 4; normal highs reach 90°
3Lows below freezing · Nov. 30 to March 2; normal lows fall below 32°
NOVEMBER 14 IN THE RECORD

On November 14 Dupo normally reaches 56° and falls to 38°. The record high is 81°, in 1971; the record low 13°, in 1940. The most rain on this date, 1.86 in, fell in 1993.

Normals 1991–2020 and records since 1874 from the St Louis Area threaded record (St Louis Lambert International Airport, 18 miles north-northwest, 120 ft higher). NOAA, through RCC-ACIS.
3

Where the rain goes

≈ 1,150 mito the Gulf of AmericaMississippi

A raindrop that lands in Dupo reaches the Gulf of America by way of the Mississippi: about 1,150 river miles.