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Shaded-relief map of Williamstown, Pennsylvania: rivers, roads, the city limits and where the water drains.
PENNSYLVANIA · DAUPHIN COUNTY

Williamstown

1,301 people, 750 ft above sea level in Dauphin County.

750 ftElevation, city center
1,301People, 2024 estimate
0 sq miLand area
Clear 47°
Clear now Dew point 32° · W 6 mph · high 45°
City of Williamstown River Interstate 2 miles
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The Williamstown 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 Williamstown

NWS forecast and National Blend of Models · updated 5:00 PM EST
RIGHT NOW Muir Army Air Field / Indiantown (KMUI) · 4:55 PM
Clear
47° Clear Feels like 44° · high of 45° near 5 PM
WindW 6 mphgusts 18
Humidity56%rising to 82% by morning
Pressure29.87 in →steady
Visibility10 mihaze-free
CloudsClear
UV index—no forecast
Dew point 32° · 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. 130.45 in · 1 dry day
ALERTS & OUTLOOKS
No watches or warnings for Dauphin County
NWS State College and the Storm Prediction Center · checked 5:47 PM
SUN & MOON
↑ 6:51 AM4:50 PM ↓
9 h 58 m of daylight, 2 minutes less than yesterday
Waxing crescent, 26% lit. Next full moon: Nov. 24.
AIR & POLLEN
22
GOODAir quality index · ozone
Tomorrow: 25, good. 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
5p
8p
11p
2a
5a
8a
11a
2p
5p
8p
11p
2a
5a
8a
11a
2p
5p
8p
11p
2a
5a
8a
11a
2p
mostly cloudy night
mostly cloudy night
partly cloudy night
mostly clear night
mostly clear night
mostly sunny
partly cloudy day
partly cloudy day
partly cloudy night
mostly clear night
mostly clear night
partly cloudy night
partly cloudy night
partly cloudy day
partly cloudy day
partly cloudy day
mostly clear night
clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
mostly sunny
clear day
TEMPERATURE °F
45°
36°
50°
35°
52°
32°
CHANCE OF RAIN
50%
WIND, MPH
10
8
8
7
6
10
12
12
7
5
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7
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2
0
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HOW IT FEELS · DEW POINT
Dry: dew points 26 to 36°

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
45° 32°
10% rain — WNW 9 A
SUN Nov. 15 Partly cloudy Partly cloudy
50° 30°
0% rain — NNW 10 A
MON Nov. 16 Partly cloudy Partly cloudy
55° 28°
0% rain — NNW 7 B
TUE Nov. 17 Partly cloudy Partly cloudy
59° 30°
0% rain — WNW 5 A
WED Nov. 18 Sunny Sunny
62° 32°
0% rain — W 5 A
THU Nov. 19 Mostly sunny Mostly sunny
64° 36°
0% rain — SW 5 A
FRI Nov. 20 Mostly sunny Mostly sunny
65° 38°
0% rain — NW 5 B
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 Williamstown about 5,000 feet above the ground was over the Canadian Prairies three days ago, and over the Great Lakes a day ago, about 2,150 miles back along its path. Near the ground the air came from Canada; at 10,000 feet, from the Gulf of Alaska. 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 1993 Nov. 15, 1993

The hottest this week has been

75° on Nov. 15, 1993, the hottest reading for this week of the year since 1948. Next is 74° in 1973.

74°
75°
19731993
Source: NOAA RCC-ACIS, the Lebanon 2 W record since 1948.
MILE2
THE GROUND

What Williamstown stands on

Williamstown’s center stands about 750 ft above sea level. Within three miles the land runs from 710 ft to 1,760 ft, a difference of 1,050 ft: steep hill country. The highest named summit within 15 miles is Big Lick Mountain, about 1,820 ft, 2 miles northeast.

Under the town center the state geologic map shows Mauch Chunk Formation (shale, siltstone, sandstone), from the Carboniferous, 324 to 359 million years old.

The section below crosses 13 rock units mapped at the surface.

Union to West Cameron, cut in half

A section south to north, 24 miles through the town center
500 ft1,000 ft1,500 ft WILLIAMSTOWN750 ftUnion520 ft ← S · UnionWest Cameron · N →

Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 15×. 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

Mauch Chunk Formation

Shale, siltstone, sandstone. Age: Carboniferous, 324 to 359 million years old. About 6 mi of the line.

Pocono Formation

Sandstone. Age: Carboniferous, 324 to 359 million years old. About 4 mi of the line.

Hamburg sequence rocks

Shale. Age: Ordovician, 445 to 487 million years old. About 3 mi of the line.

Trimmers Rock Formation

Siltstone, shale. Age: Late Devonian, 359 to 384 million years old. About 2 mi of the line.

Duncannon Member of Catskill Formation

Sandstone, siltstone. Age: Late Devonian, 359 to 384 million years old. About 2 mi of the line.

Pottsville Formation

Sandstone. Age: Carboniferous, 299 to 324 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. 7 smaller units 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 Williamstown’s rain goes

A raindrop that lands in Williamstown reaches Chesapeake Bay and the Atlantic Ocean by way of Wiconisco Creek and the Susquehanna: about 140 river miles.

THE WAY DOWN, TO SCALE
Williamstown≈ 140 mi · Chesapeake Bay and the Atlantic Ocean
FROM THE CENTER OF WILLIAMSTOWN ≈ 140 mi to Chesapeake Bay and the Atlantic Ocean Wiconisco Creek → Susquehanna

Lake on the way: Lake Aldred.

55 miles of the trip are on the Susquehanna.

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

MILE5
THE ALMANAC

Williamstown’s year

1991–2020 normals · records since 1948 · Lebanon 2 W, 19 mi south-southeast

Williamstown has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 22° in January. A normal year brings about 24 inches of snow; with the rain, that comes to about 46 inches of water.

37°22°41°24°49°31°62°40°72°51°80°60°84°64°82°63°76°55°64°44°52°34°42°27° JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 12 TODAY WILLIAMSTOWN 46.4 in rain and snowmelt
Normal high to low, by month Record high to low, by day Rain by month Freezing
July, average84° / 64°high / low, the warmest month
January, average37° / 22°high / low, the coldest month
Rain and melted snow46.4 inwettest months: July and August
Snow a year24.0 insnowiest: February
Hottest on record103°FJuly 4, 1966
Coldest on record−22°FJanuary 22, 1985
Wettest day on record8.85 inJune 22, 1972
Snowiest day on record24.0 inJanuary 23, 2016
90° days a year13very few reach 100°
Nights at or below 32°120and 23 days that stay below freezing
Climate typeHot-summer humid continentalKöppen Dfa

AROUND THE RING

1Freeze seasonfrom the first fall freeze, about Oct. 22, to the last in spring, about April 23 (median dates)
2Lows below freezingNov. 21 to March 22; normal lows fall below 32°
NOVEMBER 14 IN THE RECORD

On November 14 Williamstown normally reaches 53° and falls to 34°. The record high is 72°, in 1989; the record low 17°, in 1986. The most rain on this date, 1.69 in, fell in 1972.

MONTH BY MONTH
JanFebMarAprMayJunJulAugSepOctNovDec
Normal high37°41°49°62°72°80°84°82°76°64°52°42°
Normal low22°24°31°40°51°60°64°63°55°44°34°27°
Rain and melt, in3.062.553.603.723.994.494.854.634.634.103.213.57
Snow, inches6.87.84.20.40.00.00.00.00.00.30.54.0
Record high70° (1967)79° (2018)84° (1998)91° (2002)95° (2026)100° (1966)103° (1966)98° (2002)98° (1983)90° (2019)82° (1982)75° (1984)
Record low−22° (1985)−12° (1979)−4° (1989)18° (1982)27° (2005)37° (1986)44° (1988)38° (1982)30° (1974)18° (1975)9° (1976)−4° (2017)

Normals 1991–2020 and records since 1948 at Lebanon 2 W, 19 miles south-southeast, 300 ft lower. NOAA, through RCC-ACIS.

MILE7
ON THE NETWORK

Around Williamstown on the Forecast Network

Neighboring plates

Harrisburg PA · 25 MI 25 miles southwest Reading PA · 40 MI 40 miles southeast Philadelphia PA · 88 MI 88 miles southeast Baltimore MD · 88 MI 88 miles south Washington DC · 118 MI 118 miles south New York NY · 141 MI 141 miles east
FORECASTCITY
Map of Williamstown, Pennsylvania. Explore the plate
PENNSYLVANIA · DAUPHIN

Williamstown

1,301 people, 750 ft above sea level in Dauphin County.

750 ftElevation
1,301People
0 sq miLand
Clear 47°
ClearDew point 32°
1

Today in Williamstown

NEXT 15 HOURS
Now mostly cloudy night 45° 0%
8p mostly cloudy night 41° 4%
11p partly cloudy night 40° 2%
2a partly cloudy night 38° 1%
5a mostly clear night 37° 0%
8a mostly sunny 38° 0%
Clear
NEXT RAINNone this week
→
Sat10%
Partly cloudy Partly cloudy
32
45
A
Sun0%
Partly cloudy Partly cloudy
30
50
A
Mon0%
Partly cloudy Partly cloudy
28
55
B
Tue0%
Partly cloudy Partly cloudy
30
59
A
Wed0%
Sunny Sunny
32
62
A
Thu0%
Mostly sunny Mostly sunny
36
64
A
Fri0%
Mostly sunny Mostly sunny
38
65
B
Letters show how sure the forecast is: A, models agree; B, some spread; C, check back. Sample data.
THIS WEEK IN 1993 · NOV. 15, 1993

75°, the hottest this week of the year has been since 1948.

2

What Williamstown stands on

Williamstown’s center stands about 750 ft above sea level. Within three miles the land runs from 710 ft to 1,760 ft, a difference of 1,050 ft: steep hill country. The highest named summit within 15 miles is Big Lick Mountain, about 1,820 ft, 2 miles northeast.

Williamstown, south to north Williamstown750 ft ← SN → 24 miles through the town center; vertical exaggeration about 28×. Colors: rock at the surface.
Elevation, center750 ft
Within 3 miles710 to 1,760 ft
Lie of the landSteep hill country (1,050 ft of relief)
High point nearbyBig Lick Mountain, 1,820 ft, 2 mi northeast
Rock at the surfaceMauch Chunk Formation
Its ageCarboniferous, 324 to 359 million years old
5

Williamstown’s year

Williamstown has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 22° in January. A normal year brings about 24 inches of snow; with the rain, that comes to about 46 inches of water.

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 12 46.4 in
July, average84° / 64° · high / low, the warmest month
January, average37° / 22° · high / low, the coldest month
Rain and melted snow46.4 in · wettest months: July and August
Snow a year24.0 in · snowiest: February
Hottest on record103°F · July 4, 1966
Coldest on record−22°F · January 22, 1985
Wettest day on record8.85 in · June 22, 1972
Snowiest day on record24.0 in · January 23, 2016
90° days a year13 · very few reach 100°
Nights at or below 32°120 · and 23 days that stay below freezing
Climate typeHot-summer humid continental · Köppen Dfa
1Freeze season · from the first fall freeze, about Oct. 22, to the last in spring, about April 23 (median dates)
2Lows below freezing · Nov. 21 to March 22; normal lows fall below 32°
NOVEMBER 14 IN THE RECORD

On November 14 Williamstown normally reaches 53° and falls to 34°. The record high is 72°, in 1989; the record low 17°, in 1986. The most rain on this date, 1.69 in, fell in 1972.

Normals 1991–2020 and records since 1948 at Lebanon 2 W, 19 miles south-southeast, 300 ft lower. NOAA, through RCC-ACIS.
3

Where the rain goes

≈ 140 mito the AtlanticWiconisco Creek → Susquehanna

A raindrop that lands in Williamstown reaches Chesapeake Bay and the Atlantic Ocean by way of Wiconisco Creek and the Susquehanna: about 140 river miles.

Lake on the way: Lake Aldred.

55 miles of the trip are on the Susquehanna.