Chambersburg weather in September

In September, Chambersburg sees average daytime highs of 75°F and overnight lows near 57°F, with 4.0 in of rain across 9.3 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 80°F in the first days to 71°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 Chambersburg's 2nd-clearest and 9th-windiest month. For the whole year in context, see Chambersburg's year-round climate.

Daytime high
75°
4th warmest
Overnight low
57°
9th coldest
Rainfall
4.0 in
9.3 wet days
Daylight
12 h 18 min
5:57 AM – 6:13 PM
Cloud cover
56%
2nd clearest
Wind
5 mph
9th windiest
Solar energy
4.22 kWh/m²
Travel score
6.9
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 80°F in the first days to 71°F by the end.

A typical September day in Chambersburg reaches about 75°F in the afternoon and slips back to 57°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 66°F and 85°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)
18062
28062
38062
48061
57961
67961
77960
87860
97860
107859
117759
127759
137658
147658
157658
167557
177557
187456
197456
207456
217355
227355
237355
247254
257254
267153
277153
287153
297052
307052

How September really feels in Chambersburg

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.

Chambersburg 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
Jan37° / 23°3.194.39.50.0
Feb40° / 25°2.78.54.310.40.2
Mar49° / 32°3.810.53.211.72.1
Apr62° / 43°3.6110.4135.0
May71° / 52°3.812.4014.26.1
Jun80° / 61°3.510.8014.86.3
Jul84° / 66°3.510.1014.55.5
Aug82° / 65°2.89.1013.66.2
Sep75° / 57°4.09.3012.36.9
Oct63° / 46°3.38.20.210.95.8
Nov51° / 36°3.18.20.99.82.7
Dec41° / 28°3.38.62.79.20.2

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 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15149
25248
35248
45248
55248
65248
75248
85248
95347
105347
115248
125248
135347
145347
155347
165248
175248
185248
195248
205149
215248
225248
235248
245248
255248
265248
275347
285347
295347
305347

Chance of precipitation in September

Any precipitation

Chambersburg gets around 4.0 in of rain over 9.3 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
529
629
729
829
929
1029
1128
1228
1328
1428
1528
1628
1728
1829
1929
2030
2130
2231
2331
2432
2532
2632
2732
2832
2931
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 47% of days. Sticky, muggy-or-worse air turns up on roughly 14% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1272720224
2292720214
3302719214
4312619204
5332619193
6352619183
7362519173
8382519163
9392419162
10412319152
11422319152
12432219141
13452219131
14462219131
15472119121
16482119111
17502118110
18512118100
19522018100
2053201890
2155201780
2255201780
2357201670
2457201670
2560191560
2660191560
2761191460
2863181450
2964181350
3065171350

Wind in September

Winds average 5 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
165calm
175calm
185calm
195calm
205calm
215calm
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 5:43 AM to 6:11 AM, and sunset from 6:38 PM to 5:49 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:436:38
212.95:446:36
312.85:456:35
412.85:466:33
512.75:476:31
612.75:476:30
712.75:486:28
812.65:496:26
912.65:506:25
1012.55:516:23
1112.55:526:21
1212.45:536:20
1312.45:546:18
1412.35:556:16
1512.35:566:14
1612.35:576:13
1712.25:586:11
1812.25:596:09
1912.16:006:08
2012.16:016:06
2112.06:026:04
2212.06:036:02
2311.96:046:01
2411.96:055:59
2511.96:065:57
2611.86:075:56
2711.86:085:54
2811.76:095:52
2911.76:105:51
3011.66:115:49

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.22 kWh/m².

For context, solar energy here swings from a low near 1.75 kWh/m² to a high of 6.08 kWh/m² in June across the year — September's 4.22 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.8Bright
34.7Bright
44.7Bright
54.7Bright
64.6Bright
74.6Bright
84.5Bright
94.5Bright
104.5Bright
114.4Bright
124.4Bright
134.3Bright
144.3Bright
154.3Bright
164.2Bright
174.2Bright
184.2Bright
194.1Bright
204.1Bright
214.0Bright
224.0Moderate
233.9Moderate
243.9Moderate
253.9Moderate
263.8Moderate
273.8Moderate
283.8Moderate
293.7Moderate
303.7Moderate
Planning a trip in September

Is September a good time to visit Chambersburg?

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
5.8
Beach & pool
4th-best month of the year

September is a reasonable time to visit Chambersburg for sightseeing.

What to pack for Chambersburg in September

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

In September, Chambersburg sees daytime highs around 75°F and nights near 57°F. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

UV index in Chambersburg 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 Chambersburg peaks around June 22 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 22UV 9Dec 20UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Chambersburg 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 Chambersburg is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (November, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1316 µg/m³Nov 137 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar12Good
Apr12Good
May14Moderate
Jun16Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov7Good
Dec8Good
Location & terrain

Where is Chambersburg?

Chambersburg sits at 39.9°N, 77.7°W, 617 ft above sea level, in United States. The nearest listed city is Hagerstown, 21 mi away.

Topography around Chambersburg

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

Within 2 miles, the terrain around Chambersburg has only modest variations in elevation — a maximum elevation change of 220 ft around an average of 659 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,877 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,802 ft.

The land around Chambersburg is covered by trees (30%), artificial surfaces (29%) and grassland (26%) within 2 miles, trees (40%), cropland (34%) and grassland (21%) within 10 miles, and trees (64%) within 50 miles.

2 miles
220 ft
10 miles
1,877 ft
50 miles
2,802 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Hagerstown 21 mi · Carlisle 31 mi · Martinsburg 37 mi · Hanover 37 mi · Frederick 39 mi · Ballenger Creek 41 mi · Westminster 43 mi · Harrisburg 47 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 Chambersburg (39.9376°, -77.6611°, elevation 617 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. 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).