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

Posen

5,413 people, 610 ft above sea level in Cook County.

610 ftElevation, city center
5,413People, 2024 estimate
1 sq miLand area
Sunny 45°
Sunny now Dew point 31° · NW 8 mph · high 45°
City of Posen River Interstate 2 miles
Explore the plate Order a print

The Posen 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 Posen

NWS forecast and National Blend of Models · updated 3:00 PM CST
RIGHT NOW Chicago Midway Airport (KMDW) · 3:53 PM
Sunny
45° Sunny Feels like 41° · high of 45° near 4 PM
WindNW 8 mphno gusts
Humidity58%rising to 82% by morning
Pressure30.25 in →steady
Visibility10 mihaze-free
CloudsClear
UV index—no forecast
Dew point 31° · 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. 110.09 in · 3 dry days
ALERTS & OUTLOOKS
No watches or warnings for Cook County
NWS Chicago and the Storm Prediction Center · checked 4:16 PM
SUN & MOON
↑ 6:38 AM4:32 PM ↓
9 h 53 m of daylight, 2 minutes less than yesterday
Waxing crescent, 26% lit. Next full moon: Nov. 24.
AIR & POLLEN
21
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
4p
7p
10p
1a
4a
7a
10a
1p
4p
7p
10p
1a
4a
7a
10a
1p
4p
7p
10p
1a
4a
7a
10a
1p
mostly clear night
mostly clear night
clear night
mostly clear night
mostly clear night
mostly sunny
clear day
clear day
clear night
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
clear day
clear day
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
clear day
clear day
TEMPERATURE °F
45°
33°
48°
32°
50°
36°
CHANCE OF RAIN
50%
WIND, MPH
7
7
6
6
6
6
0
2
0
0
2
3
4
5
7
8
7
8
8
8
8
8
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10
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 50° / 36°
SAT Nov. 14 Mostly sunny Mostly sunny
45° 33°
0% rain — N 8 A
SUN Nov. 15 Mostly sunny Mostly sunny
51° 31°
0% rain — NW 2 A
MON Nov. 16 Sunny Sunny
52° 36°
0% rain — SW 7 A
TUE Nov. 17 Sunny Sunny
55° 39°
0% rain — S 9 A
WED Nov. 18 Partly cloudy Partly cloudy
57° 45°
0% rain — S 14 A
THU Nov. 19 Mostly sunny Mostly sunny
61° 46°
10% rain — WSW 10 B
FRI Nov. 20 Partly cloudy Partly cloudy
61° 50°
10% rain — SSE 9 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 Posen about 5,000 feet above the ground was over the open Pacific three days ago, and over the northern Plains a day ago, about 3,040 miles back along its path. It came down from about 14,000 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 IN 1989 Nov. 13, 1989

The hottest this week has been

74° on Nov. 13, 1989, the hottest reading for this week of the year since 1980. Next is 74° in 2016.

74°
74°
20161989
Source: NOAA RCC-ACIS, the Chicago Midway Airport 3 SW record since 1980.
MILE2
THE GROUND

What Posen stands on

Posen’s center stands about 610 ft above sea level. Within three miles the land runs from 580 ft to 670 ft, a difference of 90 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.

University Park to Chicago, cut in half

A section south to north, 24 miles through the town center
600 ft700 ft800 ft POSEN610 ftHigh point of the line810 ftPark Forest710 ftBlue Island650 ftEvergreen Park670 ft ← S · University ParkChicago · N →

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 24 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 Posen’s rain goes

A raindrop that lands in Posen reaches the Gulf of America by way of the East Arm Little Calumet, the Calumet Sag Channel, the Chicago Sanitary and Ship Canal, the Des Plaines, the Illinois and the Mississippi: about 1,520 river miles.

THE WAY DOWN, TO SCALE
Posen≈ 1,520 mi · the Gulf of America
FROM THE CENTER OF POSEN ≈ 1,520 mi to the Gulf of America East Arm Little Calumet → Calumet Sag Channel → Chicago Sanitary and Ship Canal → Des Plaines → 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 Posen; river miles along the main stem, rounded.

MILE5
THE ALMANAC

Posen’s year

1991–2020 normals · records since 1980 · Chicago Midway Airport 3 SW, 9 mi north-northwest

Posen has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 20° in January. A normal year brings about 39 inches of snow; with the rain, that comes to about 41 inches of water.

33°20°37°23°48°32°60°42°72°52°81°63°85°68°83°67°77°59°64°47°50°35°38°25° JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 123 TODAY POSEN 40.9 in rain and snowmelt
Normal high to low, by month Record high to low, by day Rain by month Freezing
July, average85° / 68°high / low, the warmest month
January, average33° / 20°high / low, the coldest month
Rain and melted snow40.9 inwettest months: May and June
Snow a year38.8 insnowiest: January
Hottest on record106°FJuly 13, 1995
Coldest on record−25°FJanuary 20, 1985
Wettest day on record5.72 inJuly 17, 1996
Snowiest day on record17.6 inJanuary 2, 1999
90° days a year21very few reach 100°
Nights at or below 32°108and 39 days that stay below freezing
Climate typeHot-summer humid continentalKöppen Dfa

AROUND THE RING

1Freeze seasonfrom the first fall freeze, about Oct. 30, to the last in spring, about April 10 (median dates)
2Highs below freezingJan. 14 to Jan. 26; normal highs stay below 32°
3Lows below freezingNov. 23 to March 17; normal lows fall below 32°
NOVEMBER 14 IN THE RECORD

On November 14 Posen normally reaches 50° and falls to 36°. The record high is 68°, in 2025; the record low 15°, in 1986. The most rain on this date, 1.60 in, fell in 1989.

MONTH BY MONTH
JanFebMarAprMayJunJulAugSepOctNovDec
Normal high33°37°48°60°72°81°85°83°77°64°50°38°
Normal low20°23°32°42°52°63°68°67°59°47°35°25°
Rain and melt, in2.302.122.664.154.754.534.024.103.333.862.732.33
Snow, inches12.510.15.71.00.00.00.00.00.00.11.57.9
Record high67° (1989)74° (2024)86° (2012)91° (1986)97° (2012)104° (1988)106° (1995)102° (1991)98° (1990)90° (2025)77° (2020)72° (2012)
Record low−25° (1985)−17° (1996)−4° (2002)10° (1982)28° (1981)39° (2003)48° (1983)46° (1982)34° (1984)20° (1981)7° (1986)−20° (1983)

Normals 1991–2020 and records since 1980 at Chicago Midway Airport 3 SW, 9 miles north-northwest. NOAA, through RCC-ACIS.
MILE7
ON THE NETWORK

Around Posen on the Forecast Network

Neighboring plates

Chicago IL · 14 MI 14 miles north Aurora IL · 33 MI 33 miles west Milwaukee WI · 100 MI 100 miles north Madison WI · 135 MI 135 miles northwest Fort Wayne IN · 137 MI 137 miles east Indianapolis IN · 151 MI 151 miles southeast
FORECASTCITY
Map of Posen, Illinois. Explore the plate
ILLINOIS · COOK

Posen

5,413 people, 610 ft above sea level in Cook County.

610 ftElevation
5,413People
1 sq miLand
Sunny 45°
SunnyDew point 31°
1

Today in Posen

NEXT 15 HOURS
Now mostly sunny 45° 0%
7p mostly clear night 41° 0%
10p mostly clear night 38° 0%
1a mostly clear night 36° 0%
4a mostly clear night 34° 0%
7a mostly sunny 34° 0%
Clear
NEXT RAINNone this week
→
Sat0%
Mostly sunny Mostly sunny
33
45
A
Sun0%
Mostly sunny Mostly sunny
31
51
A
Mon0%
Sunny Sunny
36
52
A
Tue0%
Sunny Sunny
39
55
A
Wed0%
Partly cloudy Partly cloudy
45
57
A
Thu10%
Mostly sunny Mostly sunny
46
61
B
Fri10%
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 IN 1989 · NOV. 13, 1989

74°, the hottest this week of the year has been since 1980.

2

What Posen stands on

Posen’s center stands about 610 ft above sea level. Within three miles the land runs from 580 ft to 670 ft, a difference of 90 ft: gently rolling country.

Posen, south to north Posen610 ftHigh point810 ft ← SN → 24 miles through the town center; vertical exaggeration about 122×. Colors: rock at the surface.
Elevation, center610 ft
Within 3 miles580 to 670 ft
Lie of the landGently rolling (90 ft of relief)
Rock at the surfaceSilurian System undivided
Its ageSilurian, 422 to 445 million years old
5

Posen’s year

Posen has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 20° in January. A normal year brings about 39 inches of snow; with the rain, that comes to about 41 inches of water.

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 123 40.9 in
July, average85° / 68° · high / low, the warmest month
January, average33° / 20° · high / low, the coldest month
Rain and melted snow40.9 in · wettest months: May and June
Snow a year38.8 in · snowiest: January
Hottest on record106°F · July 13, 1995
Coldest on record−25°F · January 20, 1985
Wettest day on record5.72 in · July 17, 1996
Snowiest day on record17.6 in · January 2, 1999
90° days a year21 · very few reach 100°
Nights at or below 32°108 · and 39 days that stay below freezing
Climate typeHot-summer humid continental · Köppen Dfa
1Freeze season · from the first fall freeze, about Oct. 30, to the last in spring, about April 10 (median dates)
2Highs below freezing · Jan. 14 to Jan. 26; normal highs stay below 32°
3Lows below freezing · Nov. 23 to March 17; normal lows fall below 32°
NOVEMBER 14 IN THE RECORD

On November 14 Posen normally reaches 50° and falls to 36°. The record high is 68°, in 2025; the record low 15°, in 1986. The most rain on this date, 1.60 in, fell in 1989.

Normals 1991–2020 and records since 1980 at Chicago Midway Airport 3 SW, 9 miles north-northwest. NOAA, through RCC-ACIS.
3

Where the rain goes

≈ 1,520 mito the Gulf of AmericaEast Arm Little Calumet → Calumet Sag Channel → Chicago Sanitary and Ship Canal → Des Plaines → Illinois → Mississippi

A raindrop that lands in Posen reaches the Gulf of America by way of the East Arm Little Calumet, the Calumet Sag Channel, the Chicago Sanitary and Ship Canal, the Des Plaines, 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.