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Shaded-relief map of Tyndall, South Dakota: rivers, roads, the city limits and where the water drains.
SOUTH DAKOTA · BON HOMME COUNTY

Tyndall

1,082 people, 1,420 ft above sea level in Bon Homme County.

1,420 ftElevation, city center
1,082People, 2024 estimate
2 sq miLand area
Sunny 48°
Sunny now Dew point 28° · SE 20 mph · high 46°
City of Tyndall River Interstate 2 miles
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The Tyndall 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 Tyndall

NWS forecast and National Blend of Models · updated 12:00 PM CST
RIGHT NOW WAGNERMUNC (KAGZ) · 1:35 PM
Sunny
48° Sunny Feels like 41° · high of 46° near 3 PM
WindSE 20 mphgusts 26
Humidity46%falling to 60% this afternoon
Pressure30.11 in →steady
Visibility10 mihaze-free
CloudsClear
UV index—no forecast
Dew point 28° · Dry45° by Tuesday: more humid
DryComfortableStickyMuggyOppressive
NEXT RAIN
Rain
Friday80% chance · showers
LIKELY AMOUNT—amounts come within 3 days
LAST RAINNov. 50.03 in · 9 dry days
ALERTS & OUTLOOKS
No watches or warnings for Bon Homme County
NWS Sioux Falls and the Storm Prediction Center · checked 1:47 PM
SUN & MOON
↑ 7:22 AM5:09 PM ↓
9 h 46 m of daylight, 2 minutes less than yesterday
Waxing crescent, 25% lit. Next full moon: Nov. 24.
AIR & POLLEN
29
GOODAir quality index · ozone
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
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mostly sunny
partly cloudy night
partly cloudy night
partly cloudy night
partly cloudy night
partly cloudy night
mostly sunny
clear day
clear day
clear night
clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
clear day
windy
mostly clear night
partly cloudy night
partly cloudy night
partly cloudy night
partly cloudy night
partly cloudy day
windy
TEMPERATURE °F
44°
35°
53°
41°
56°
43°
CHANCE OF RAIN
50%
WIND, MPH
18
15
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12
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HOW IT FEELS · DEW POINT
Dry: dew points 28 to 34° ↑ Humid air returns More humid: 45° by Tuesday

The next seven days, and how sure we are

Forecast, with the range 8 in 10 ensemble members agree on Normal, about 80° / 62°
SAT Nov. 14 Partly cloudy Partly cloudy
46° 35°
0% rain — SSE 18, gusts 28 A
SUN Nov. 15 Mostly sunny; warmer Mostly sunny; warmer
55° 40°
0% rain — S 15, gusts 28 B
MON Nov. 16 Mostly sunny Mostly sunny
58° 42°
0% rain — S 18, gusts 31 B
TUE Nov. 17 Partly cloudy Partly cloudy
55° 45°
0% rain — S 18, gusts 32 B
WED Nov. 18 Partly cloudy Partly cloudy
60° 40°
20% rain — W 12 C
THU Nov. 19 Partly cloudy; cooler Partly cloudy; cooler
50° 39°
10% rain — E 5 C
FRI Nov. 20 Showers likely Showers likely
56° 43°
80% rain 0.1–1.3″ SSE 13 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 Tyndall about 5,000 feet above the ground was over Texas three days ago, and over the southern Plains a day ago, about 880 miles back along its path. The nine paths traced from around the city fan out, so treat that as a best guess. It rose from near the ground on the way. Near the ground the air came from the Canadian Prairies; at 10,000 feet, from the northern Plains. It has stayed over land, which is why it feels dry. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.

THIS WEEK, ONE YEAR AGO Nov. 15, 2025

The hottest this week has been

83° on Nov. 15, 2025, the hottest reading for this week of the year since 1893. Next is 81° in 1953.

81°
83°
19532025
Source: NOAA RCC-ACIS, the Tyndall record since 1893.
MILE2
THE GROUND

What Tyndall stands on

Tyndall’s center stands about 1,420 ft above sea level. Within three miles the land runs from 1,360 ft to 1,450 ft, a difference of 90 ft: gently rolling country.

Under the town center the state geologic map shows Niobrara Formation (chalk, marlstone, shale), from the Late Cretaceous, 66 to 100 million years old.

The section below crosses 3 rock units mapped at the surface.

Tyndall, cut in half from northwest to southeast

A section northwest to southeast, 24 miles through the town center
1,200 ft1,400 ft1,600 ft TYNDALL1,420 ftHigh point of the line1,700 ftLow point1,250 ft ← NWBon Homme Colony · SE →

Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 43×. 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

Niobrara Formation

Chalk, marlstone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 13 mi of the line.

Pierre Shale

Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 9 mi of the line.

Carlile Shale

Shale. Age: Late Cretaceous, 66 to 100 million years old. About 2 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 Tyndall’s rain goes

A raindrop that lands in Tyndall reaches the Gulf of America by way of Lewis and Clark Lake, the Missouri and the Mississippi: about 2,000 river miles.

THE WAY DOWN, TO SCALE
Tyndall≈ 2,000 mi · the Gulf of America
FROM THE CENTER OF TYNDALL ≈ 2,000 mi to the Gulf of America Lewis and Clark Lake → Missouri → Mississippi

Lake on the way: Lewis and Clark Lake.

1,170 miles of the trip are on the Mississippi.

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

MILE5
THE ALMANAC

Tyndall’s year

1991–2020 normals · records since 1893 · Tyndall

Tyndall has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 9° in January. A normal year brings about 37 inches of snow; with the rain, that comes to about 26 inches of water.

29°9°34°13°46°23°58°34°70°47°81°58°86°63°83°60°76°51°62°37°46°24°33°13° JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 1234 TODAY TYNDALL 26.2 in rain and snowmelt
Normal high to low, by month Record high to low, by day Rain by month Freezing
July, average86° / 63°high / low, the warmest month
January, average29° / 9°high / low, the coldest month
Rain and melted snow26.2 inwettest months: May and June
Snow a year36.6 insnowiest: February
Hottest on record115°FJuly 17, 1936
Coldest on record−41°FFebruary 2, 1905
Wettest day on record6.10 inMay 21, 1903
Snowiest day on record19.0 inJanuary 19, 1988
90° days a year26about 2 of them 100° or more
Nights at or below 32°156and 56 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. 15 to Feb. 10; normal highs stay below 32°
3Lows below freezingOct. 26 to April 11; normal lows fall below 32°
4Wettest stretchMay through July: 10.7 of the year’s 26.2 inches
NOVEMBER 14 IN THE RECORD

On November 14 Tyndall normally reaches 46° and falls to 24°. The record high is 77°, in 1999; the record low −19°, in 1959. The most rain on this date, 0.84 in, fell in 1926.

MONTH BY MONTH
JanFebMarAprMayJunJulAugSepOctNovDec
Normal high29°34°46°58°70°81°86°83°76°62°46°33°
Normal low9°13°23°34°47°58°63°60°51°37°24°13°
Rain and melt, in0.570.811.352.863.963.393.333.272.702.211.010.78
Snow, inches6.57.45.34.10.20.00.00.00.00.85.07.3
Record high71° (2012)76° (2017)96° (1943)99° (1894)107° (1934)108° (1988)115° (1936)113° (1936)106° (1922)98° (1947)84° (2009)70° (1939)
Record low−38° (1912)−41° (1905)−19° (1960)−3° (1936)20° (1967)33° (1901)40° (1903)36° (1915)21° (1918)4° (1913)−19° (1959)−36° (1917)

Normals 1991–2020 and records since 1893 at Tyndall, here. NOAA, through RCC-ACIS.

MILE7
ON THE NETWORK

Around Tyndall on the Forecast Network

Neighboring plates

Yankton SD · 25 MI 25 miles east Sioux Falls SD · 69 MI 69 miles northeast Sioux City IA · 82 MI 82 miles southeast Omaha NE · 151 MI 151 miles southeast Lincoln NE · 162 MI 162 miles south
FORECASTCITY
Map of Tyndall, South Dakota. Explore the plate
SOUTH DAKOTA · BON HOMME

Tyndall

1,082 people, 1,420 ft above sea level in Bon Homme County.

1,420 ftElevation
1,082People
2 sq miLand
Sunny 48°
SunnyDew point 28°
1

Today in Tyndall

NEXT 15 HOURS
Now mostly sunny 44° 0%
4p partly cloudy day 45° 0%
7p partly cloudy night 40° 0%
10p partly cloudy night 38° 0%
1a partly cloudy night 36° 0%
4a partly cloudy night 36° 0%
Rain
NEXT RAINFriday · 80%
→
Sat0%
Partly cloudy Partly cloudy
35
46
A
Sun0%
Mostly sunny; warmer Mostly sunny; warmer
40
55
B
Mon0%
Mostly sunny Mostly sunny
42
58
B
Tue0%
Partly cloudy Partly cloudy
45
55
B
Wed20%
Partly cloudy Partly cloudy
40
60
C
Thu10%
Partly cloudy; cooler Partly cloudy; cooler
39
50
C
Fri80%
Showers likely Showers likely
43
56
C
Letters show how sure the forecast is: A, models agree; B, some spread; C, check back. Sample data.
THIS WEEK, ONE YEAR AGO · NOV. 15, 2025

83°, the hottest this week of the year has been since 1893.

2

What Tyndall stands on

Tyndall’s center stands about 1,420 ft above sea level. Within three miles the land runs from 1,360 ft to 1,450 ft, a difference of 90 ft: gently rolling country.

Tyndall, northwest to southeast Tyndall1,420 ft ← NWSE → 24 miles through the town center; vertical exaggeration about 82×. Colors: rock at the surface.
Elevation, center1,420 ft
Within 3 miles1,360 to 1,450 ft
Lie of the landGently rolling (90 ft of relief)
Rock at the surfaceNiobrara Formation
Its ageLate Cretaceous, 66 to 100 million years old
5

Tyndall’s year

Tyndall has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 9° in January. A normal year brings about 37 inches of snow; with the rain, that comes to about 26 inches of water.

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 1234 26.2 in
July, average86° / 63° · high / low, the warmest month
January, average29° / 9° · high / low, the coldest month
Rain and melted snow26.2 in · wettest months: May and June
Snow a year36.6 in · snowiest: February
Hottest on record115°F · July 17, 1936
Coldest on record−41°F · February 2, 1905
Wettest day on record6.10 in · May 21, 1903
Snowiest day on record19.0 in · January 19, 1988
90° days a year26 · about 2 of them 100° or more
Nights at or below 32°156 · and 56 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. 15 to Feb. 10; normal highs stay below 32°
3Lows below freezing · Oct. 26 to April 11; normal lows fall below 32°
4Wettest stretch · May through July: 10.7 of the year’s 26.2 inches
NOVEMBER 14 IN THE RECORD

On November 14 Tyndall normally reaches 46° and falls to 24°. The record high is 77°, in 1999; the record low −19°, in 1959. The most rain on this date, 0.84 in, fell in 1926.

Normals 1991–2020 and records since 1893 at Tyndall, here. NOAA, through RCC-ACIS.
3

Where the rain goes

≈ 2,000 mito the Gulf of AmericaLewis and Clark Lake → Missouri → Mississippi

A raindrop that lands in Tyndall reaches the Gulf of America by way of Lewis and Clark Lake, the Missouri and the Mississippi: about 2,000 river miles.

Lake on the way: Lewis and Clark Lake.

1,170 miles of the trip are on the Mississippi.