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

Jefferson

360 people, 1,160 ft above sea level in Dauphin County.

1,160 ftElevation, city center
360People, 2024 estimate
24 sq miLand area
Sunny 47°
Sunny now Dew point 32° · W 12 mph · high 47°
City of Jefferson River Interstate 2 miles
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The Jefferson 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 Jefferson

NWS forecast and National Blend of Models · updated 4:00 PM EST
RIGHT NOW Muir Army Air Field / Indiantown (KMUI) · 3:55 PM
Sunny
47° Sunny Feels like 41° · high of 47° near 4 PM
WindW 12 mphgusts 23
Humidity57%rising to 82% by morning
Pressure29.86 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 4:47 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
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 cloudy night
mostly cloudy night
partly cloudy night
partly cloudy night
mostly clear night
mostly sunny
mostly sunny
mostly cloudy day
mostly cloudy night
mostly clear night
mostly clear night
mostly clear night
mostly clear night
mostly sunny
mostly sunny
mostly sunny
mostly clear night
clear night
clear night
mostly clear night
mostly clear night
mostly sunny
mostly sunny
mostly sunny
TEMPERATURE °F
47°
36°
50°
35°
52°
32°
CHANCE OF RAIN
50%
WIND, MPH
12
9
8
7
7
8
12
12
8
5
4
3
3
5
9
7
4
0
0
0
0
1
4
5
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 Mostly cloudy Mostly cloudy
47° 32°
0% rain — WNW 12 A
SUN Nov. 15 Partly cloudy Partly cloudy
50° 30°
0% rain — NNW 10 A
MON Nov. 16 Mostly sunny Mostly sunny
55° 28°
0% rain — NNW 7 B
TUE Nov. 17 Sunny Sunny
59° 30°
0% rain — WNW 5 A
WED Nov. 18 Sunny Sunny
62° 32°
0% rain — W 5 A
THU Nov. 19 Partly cloudy Partly cloudy
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 Jefferson about 5,000 feet above the ground was over British Columbia three days ago, and over the Great Lakes a day ago, about 2,280 miles back along its path. Near the ground the air came from the central Plains; 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 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 Jefferson stands on

Jefferson’s center stands about 1,160 ft above sea level. Within three miles the land runs from 660 ft to 1,630 ft, a difference of 970 ft: steep hill country. The highest named summit within 15 miles is Big Lick Mountain, about 1,820 ft, 9 miles northeast.

The section below crosses 8 rock units mapped at the surface.

Middle Paxton to Valley View, cut in half

A section southwest to northeast, 24 miles through the town center
500 ft1,000 ft1,500 ft JEFFERSON1,160 ftLow point440 ftWilliamstown710 ftValley View800 ft ← SW · Middle PaxtonValley View · NE →

Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 14×. 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 8 mi of the line.

Pocono Formation

Sandstone. Age: Carboniferous, 324 to 359 million years old. About 5 mi of the line.

Pottsville Formation

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

Duncannon Member of Catskill Formation

Sandstone, siltstone. Age: Late Devonian, 359 to 384 million years old. About 3 mi of the line.

Sherman Creek Member of Catskill Formation

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

Spechty Kopf Formation

Sandstone. Age: Devonian to Carboniferous, 324 to 422 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. 2 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 Jefferson’s rain goes

A raindrop that lands in Jefferson reaches Chesapeake Bay and the Atlantic Ocean by way of Smoke Hole Run, South Fork Powells Creek, Powells Creek and the Susquehanna: about 110 river miles.

THE WAY DOWN, TO SCALE
Jefferson≈ 110 mi · Chesapeake Bay and the Atlantic Ocean
FROM THE CENTER OF JEFFERSON ≈ 110 mi to Chesapeake Bay and the Atlantic Ocean Smoke Hole Run → South Fork Powells Creek → Powells Creek → Susquehanna

Lake on the way: Lake Aldred.

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

MILE5
THE ALMANAC

Jefferson’s year

1991–2020 normals · records since 1948 · Lebanon 2 W, 18 mi southeast

Jefferson 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 JEFFERSON 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 Jefferson 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, 18 miles southeast, 710 ft lower. NOAA, through RCC-ACIS.

MILE7
ON THE NETWORK

Around Jefferson on the Forecast Network

Neighboring plates

Lower Paxton PA · 14 MI 14 miles south Lancaster PA · 39 MI 39 miles southeast Philadelphia PA · 90 MI 90 miles southeast Washington DC · 112 MI 112 miles south New York NY · 146 MI 146 miles east Hempstead NY · 163 MI 163 miles east
FORECASTCITY
Map of Jefferson, Pennsylvania. Explore the plate
PENNSYLVANIA · DAUPHIN

Jefferson

360 people, 1,160 ft above sea level in Dauphin County.

1,160 ftElevation
360People
24 sq miLand
Sunny 47°
SunnyDew point 32°
1

Today in Jefferson

NEXT 15 HOURS
Now mostly cloudy day 47° 0%
7p mostly cloudy night 42° 1%
10p partly cloudy night 40° 2%
1a partly cloudy night 39° 1%
4a mostly clear night 37° 0%
7a mostly sunny 36° 0%
Clear
NEXT RAINNone this week
→
Sat0%
Mostly cloudy Mostly cloudy
32
47
A
Sun0%
Partly cloudy Partly cloudy
30
50
A
Mon0%
Mostly sunny Mostly sunny
28
55
B
Tue0%
Sunny Sunny
30
59
A
Wed0%
Sunny Sunny
32
62
A
Thu0%
Partly cloudy Partly cloudy
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 Jefferson stands on

Jefferson’s center stands about 1,160 ft above sea level. Within three miles the land runs from 660 ft to 1,630 ft, a difference of 970 ft: steep hill country. The highest named summit within 15 miles is Big Lick Mountain, about 1,820 ft, 9 miles northeast.

Jefferson, southwest to northeast Jefferson1,160 ft ← SWNE → 24 miles through the town center; vertical exaggeration about 27×. Colors: rock at the surface.
Elevation, center1,160 ft
Within 3 miles660 to 1,630 ft
Lie of the landSteep hill country (970 ft of relief)
High point nearbyBig Lick Mountain, 1,820 ft, 9 mi northeast
5

Jefferson’s year

Jefferson 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 Jefferson 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, 18 miles southeast, 710 ft lower. NOAA, through RCC-ACIS.
3

Where the rain goes

≈ 110 mito the AtlanticSmoke Hole Run → South Fork Powells Creek → Powells Creek → Susquehanna

A raindrop that lands in Jefferson reaches Chesapeake Bay and the Atlantic Ocean by way of Smoke Hole Run, South Fork Powells Creek, Powells Creek and the Susquehanna: about 110 river miles.

Lake on the way: Lake Aldred.