Harrisburg weather in September

In September, Harrisburg sees average daytime highs of 76°F and overnight lows near 59°F, with 4.3 in of rain across 9 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 1st-wettest month of the year here.

Highs ease over the month, from about 81°F in the first days to 72°F by the end. The sky is clear or mostly clear about 35% of the time in September, and the air most often feels dry.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Harrisburg's 2nd-clearest and 9th-windiest month. For the whole year in context, see Harrisburg's year-round climate.

Daytime high
76°
4th warmest
Overnight low
59°
9th coldest
Rainfall
4.3 in
9 wet days
Daylight
12 h 18 min
5:54 AM – 6:10 PM
Cloud cover
56%
2nd clearest
Wind
6 mph
9th windiest
Solar energy
4.2 kWh/m²
Travel score
6.9
out of 10

Harrisburg is capital city of the U.S. state of Pennsylvania and seat of Dauphin County.

Density
1,633/km²
people per km²
Founded
1719

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 81°F in the first days to 72°F by the end.

A typical September day in Harrisburg reaches about 76°F in the afternoon and slips back to 59°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 67°F and 86°F. Set against its neighbours, September runs about 7°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18164
28163
38163
48063
58063
68062
78062
87962
97961
107861
117860
127860
137760
147759
157759
167659
177658
187558
197558
207557
217457
227456
237456
247356
257355
267255
277255
287254
297154
307153

How September really feels in Harrisburg

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Harrisburg weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan38° / 25°3.394.59.50.0
Feb41° / 26°2.88.94.210.40.2
Mar50° / 33°3.810.63.211.72.3
Apr63° / 44°3.610.60.3135.2
May72° / 53°3.512014.26.3
Jun81° / 63°3.411014.86.1
Jul85° / 68°3.610.3014.65.2
Aug83° / 66°3.19.6013.65.9
Sep76° / 59°4.39012.36.9
Oct64° / 47°3.58.30.110.95.9
Nov53° / 37°3.18.20.79.83.0
Dec43° / 30°3.59.22.99.20.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15446
25347
35347
45446
55347
65347
75347
85446
95446
105446
115446
125446
135446
145446
155446
165347
175347
185347
195248
205248
215248
225248
235248
245248
255248
265248
275248
285248
295248
305248

Chance of precipitation in September

Any precipitation

Harrisburg gets around 4.3 in of rain over 9 wet days in September, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 29% and peaks near 32% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
127
228
328
428
528
628
728
827
927
1027
1127
1227
1327
1427
1527
1628
1728
1829
1929
2030
2130
2231
2331
2432
2532
2632
2732
2832
2932
3031

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 43% of days. Sticky, muggy-or-worse air turns up on roughly 16% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1232623236
2242622226
3252522226
4272621215
5282620205
6302620205
7312519195
8332519184
9342519184
10362519174
11372419173
12392418163
13402318163
14422318152
15432218142
16442218132
17462218131
18472118121
19492118111
20502118101
21512018101
2252201891
2354201781
2455201780
2557191770
2658191670
2759191660
2860181660
2961181560
3063171550

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 5 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 min at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over September. Sunrise moves from 5:39 AM to 6:08 AM, and sunset from 6:35 PM to 5:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:396:35
212.95:406:34
312.85:416:32
412.85:426:30
512.85:436:29
612.75:446:27
712.75:456:25
812.65:466:24
912.65:476:22
1012.55:486:20
1112.55:496:18
1212.45:506:17
1312.45:516:15
1412.45:526:13
1512.35:536:11
1612.35:546:10
1712.25:556:08
1812.25:566:06
1912.15:576:05
2012.15:586:03
2112.05:596:01
2212.06:005:59
2311.96:015:58
2411.96:025:56
2511.96:035:54
2611.86:045:52
2711.86:055:51
2811.76:065:49
2911.76:075:47
3011.66:085:46

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.2 kWh/m².

For context, solar energy here swings from a low near 1.73 kWh/m² to a high of 6.06 kWh/m² in June across the year — September's 4.2 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.7Bright
34.7Bright
44.7Bright
54.6Bright
64.6Bright
74.5Bright
84.5Bright
94.5Bright
104.4Bright
114.4Bright
124.4Bright
134.3Bright
144.3Bright
154.2Bright
164.2Bright
174.2Bright
184.1Bright
194.1Bright
204.0Bright
214.0Bright
224.0Moderate
233.9Moderate
243.9Moderate
253.8Moderate
263.8Moderate
273.8Moderate
283.7Moderate
293.7Moderate
303.7Moderate
Planning a trip in September

Hazard calendar for Harrisburg

In seasonPeak

In September, Harrisburg sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Harrisburg sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Harrisburg?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

6.9
Sightseeing
1st-best month of the year
6.0
Beach & pool
4th-best month of the year

September is a reasonable time to visit Harrisburg for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Harrisburg in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Harrisburg sees daytime highs around 76°F and nights near 59°F. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

UV index in Harrisburg in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Harrisburg peaks around June 22 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 22UV 8Dec 21UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Harrisburg in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Harrisburg is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (November, 8 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1316 µg/m³Nov 118 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar12Moderate
Apr13Moderate
May14Moderate
Jun16Moderate
Jul17Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Harrisburg?

Harrisburg sits at 40.3°N, 76.9°W, 331 ft above sea level, in United States. The nearest listed city is Carlisle, 17 mi away.

Topography around Harrisburg

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Harrisburg.

Within 2 miles, the terrain around Harrisburg has only modest variations in elevation — a maximum elevation change of 335 ft around an average of 367 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,260 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,300 ft.

The land around Harrisburg is covered by artificial surfaces (39%), trees (32%) and water (21%) within 2 miles, trees (59%) within 10 miles, and trees (58%) and cropland (22%) within 50 miles.

2 miles
335 ft
10 miles
1,260 ft
50 miles
2,300 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Carlisle 17 mi · York 23 mi · Lebanon 25 mi · Hanover 33 mi · Lancaster 35 mi · Chambersburg 47 mi · Westminster 48 mi · Reading 50 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Harrisburg (40.2737°, -76.8844°, elevation 331 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).