Pottstown weather in September

In September, Pottstown sees average daytime highs of 76°F and overnight lows near 58°F, with 4.4 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 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 Pottstown's 2nd-clearest and 9th-windiest month. For the whole year in context, see Pottstown's year-round climate.

Daytime high
76°
4th warmest
Overnight low
58°
9th coldest
Rainfall
4.4 in
9.3 wet days
Daylight
12 h 18 min
5:49 AM – 6:05 PM
Cloud cover
56%
2nd clearest
Wind
6 mph
9th windiest
Solar energy
4.23 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 81°F in the first days to 72°F by the end.

A typical September day in Pottstown reaches about 76°F in the afternoon and slips back to 58°F overnight — a 18°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)
18163
28163
38163
48162
58062
68062
78062
87961
97961
107960
117860
127860
137859
147759
157759
167658
177658
187657
197557
207557
217456
227456
237456
247355
257355
267355
277254
287254
297153
307153

How September really feels in Pottstown

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.

Pottstown 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°3.39.34.19.50.0
Feb41° / 26°3.093.910.40.3
Mar50° / 33°4.010.83.311.72.2
Apr62° / 43°3.9110.4135.1
May72° / 53°3.711.4014.26.3
Jun81° / 62°4.011.6014.86.0
Jul86° / 67°4.011.3014.64.9
Aug83° / 66°3.710.2013.65.7
Sep76° / 58°4.49.3012.36.9
Oct64° / 47°3.88.70.110.95.9
Nov53° / 37°3.07.90.69.83.1
Dec43° / 30°3.89.12.49.20.5

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 15% of September, with mostly cloudy or overcast conditions the remaining 50%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15149
25050
35050
45050
54951
65050
75050
85050
95149
105050
115050
125050
135149
145050
155149
165050
175050
185050
195050
205050
215050
225050
235050
245050
255149
265149
275149
285248
295248
305248

Chance of precipitation in September

Any precipitation

Pottstown gets around 4.4 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 30% and peaks near 33% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
128
228
328
428
529
629
729
829
929
1029
1129
1229
1329
1429
1529
1629
1729
1830
1930
2031
2131
2232
2332
2432
2533
2633
2733
2833
2933
3033

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 44% of days. Sticky, muggy-or-worse air turns up on roughly 17% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1262421227
2272420227
3282420217
4292420217
5302419207
6322419197
7332419186
8342418186
9352418176
10362318166
11382318165
12392318155
13402218155
14412219144
15432219134
16442119133
17452119123
18472019113
19482019112
20492019112
21501919102
22511918102
23531818101
2454181891
2556171791
2656171791
2760161680
2860161680
2961161580
3063151570

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
116calm
126calm
136calm
146calm
156calm
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 5:34 AM to 6:03 AM, and sunset from 6:30 PM to 5:41 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:346:30
212.95:356:29
312.85:366:27
412.85:376:25
512.85:386:24
612.75:396:22
712.75:406:20
812.65:416:19
912.65:426:17
1012.55:436:15
1112.55:446:13
1212.45:456:12
1312.45:466:10
1412.45:476:08
1512.35:486:07
1612.35:496:05
1712.25:506:03
1812.25:516:01
1912.15:526:00
2012.15:535:58
2112.05:545:56
2212.05:555:54
2311.95:565:53
2411.95:575:51
2511.95:585:49
2611.85:595:47
2711.86:005:46
2811.76:015:44
2911.76:025:42
3011.66:035:41

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.23 kWh/m².

For context, solar energy here swings from a low near 1.77 kWh/m² to a high of 6.06 kWh/m² in June across the year — September's 4.23 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
234.0Moderate
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 Pottstown?

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 Pottstown for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Pottstown in September

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

In September, Pottstown sees daytime highs around 76°F and nights near 58°F. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

UV index in Pottstown 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 Pottstown peaks around July 10 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 highHighModerateLowJul 10UV 8Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov3Moderate
Dec2Low

Air quality in Pottstown 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 Pottstown 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 1417 µg/m³Nov 148 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb12Good
Mar13Moderate
Apr13Moderate
May16Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep12Good
Oct9Good
Nov8Good
Dec9Good
Location & terrain

Where is Pottstown?

Pottstown sits at 40.2°N, 75.6°W, 151 ft above sea level, in United States. The nearest listed city is Limerick, 6.8 mi away.

Topography around Pottstown

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

Within 2 miles, the terrain around Pottstown has only modest variations in elevation — a maximum elevation change of 410 ft around an average of 220 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,076 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,336 ft.

The land around Pottstown is covered by trees (50%), artificial surfaces (24%) and grassland (20%) within 2 miles, trees (62%) and grassland (25%) within 10 miles, and trees (58%) within 50 miles.

2 miles
410 ft
10 miles
1,076 ft
50 miles
2,336 ft
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Limerick 6.8 mi · Phoenixville 11 mi · Reading 16 mi · King of Prussia 17 mi · Norristown 19 mi · Lansdale 19 mi · Wayne 20 mi · West Chester 20 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 Pottstown (40.2454°, -75.6496°, elevation 151 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).