Altoona weather in September

In September, Altoona sees average daytime highs of 71°F and overnight lows near 53°F, with 4.1 in of rain across 10.2 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 76°F in the first days to 67°F by the end. The sky is clear or mostly clear about 32% 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 Altoona's 1st-clearest and 10th-windiest month. For the whole year in context, see Altoona's year-round climate.

Daytime high
71°
4th warmest
Overnight low
53°
9th coldest
Rainfall
4.1 in
10.2 wet days
Daylight
12 h 18 min
6:00 AM – 6:16 PM
Cloud cover
57%
1st clearest
Wind
6 mph
10th windiest
Solar energy
4.12 kWh/m²
Travel score
6.6
out of 10

Altoona is city in Blair County, Pennsylvania, United States.

Density
1,767/km²
people per km²
Founded
1849

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 76°F in the first days to 67°F by the end.

A typical September day in Altoona reaches about 71°F in the afternoon and slips back to 53°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 61°F and 81°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)
17658
27658
37658
47557
57557
67557
77456
87456
97456
107455
117355
127355
137354
147254
157253
167153
177153
187152
197052
207052
217051
226951
236951
246850
256850
266749
276749
286749
296648
306648

How September really feels in Altoona

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.

Altoona weather by month

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

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan33° / 20°3.110.97.69.40.0
Feb36° / 21°2.8106.710.40.0
Mar45° / 28°3.912.1511.70.9
Apr58° / 39°4.213.41.3133.8
May67° / 49°4.614.6014.25.4
Jun75° / 57°4.412.7014.86.3
Jul79° / 62°3.912.4014.66.3
Aug78° / 60°3.311.2013.66.5
Sep71° / 53°4.110.2012.36.6
Oct59° / 42°3.59.80.510.94.7
Nov47° / 33°3.19.62.19.71.6
Dec38° / 25°3.210.25.59.20.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 32% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 50%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15149
25248
35248
45248
55248
65149
75149
85149
95149
105050
115050
125050
135050
144951
154951
165050
174951
184951
194951
204951
214951
224951
235050
245050
255050
265050
275050
284951
294951
305050

Chance of precipitation in September

Any precipitation

Altoona gets around 4.1 in of rain over 10.2 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 33% and peaks near 35% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
132
233
333
433
533
633
733
833
932
1032
1132
1232
1332
1431
1531
1632
1732
1832
1932
2033
2133
2234
2334
2434
2535
2635
2735
2835
2934
3034

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 55% of days. Sticky, muggy-or-worse air turns up on roughly 8% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1352424161
2362423161
3372422161
4382422151
5402421141
6422420141
7432419131
8452419121
9462319121
10482318110
11492318100
1251221890
1352221790
1454211780
1555211770
1657201670
1758201660
1860191650
1961191550
2063181540
2163181540
2266171430
2366171430
2468161420
2569161320
2669161320
2772151210
2872151210
2973151110
3074141110

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
96calm
106calm
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 5:45 AM to 6:14 AM, and sunset from 6:42 PM to 5:52 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:456:42
212.95:466:40
312.95:476:38
412.85:486:37
512.85:496:35
612.75:506:33
712.75:516:31
812.65:526:30
912.65:536:28
1012.55:546:26
1112.55:556:25
1212.45:566:23
1312.45:576:21
1412.45:586:19
1512.35:596:18
1612.36:006:16
1712.26:016:14
1812.26:026:12
1912.16:036:11
2012.16:046:09
2112.06:056:07
2212.06:066:05
2311.96:076:04
2411.96:086:02
2511.96:096:00
2611.86:105:58
2711.86:115:57
2811.76:125:55
2911.76:135:53
3011.66:145:52

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.12 kWh/m².

For context, solar energy here swings from a low near 1.59 kWh/m² to a high of 5.92 kWh/m² in June across the year — September's 4.12 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.6Bright
44.6Bright
54.5Bright
64.5Bright
74.5Bright
84.4Bright
94.4Bright
104.3Bright
114.3Bright
124.3Bright
134.2Bright
144.2Bright
154.2Bright
164.1Bright
174.1Bright
184.0Bright
194.0Bright
204.0Moderate
213.9Moderate
223.9Moderate
233.9Moderate
243.8Moderate
253.8Moderate
263.7Moderate
273.7Moderate
283.6Moderate
293.6Moderate
303.6Moderate
Planning a trip in September

Is September a good time to visit Altoona?

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

6.6
Sightseeing
1st-best month of the year
4.5
Beach & pool
4th-best month of the year

September is a reasonable time to visit Altoona for sightseeing.

What to pack for Altoona in September

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

In September, Altoona sees daytime highs around 71°F and nights near 53°F. Worth packing: rain gear. About 10 days see rain.

rain gear

UV index in Altoona 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 Altoona peaks around June 23 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 23UV 9Dec 20UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Altoona 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 Altoona 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 147 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar11Good
Apr12Good
May14Moderate
Jun16Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov7Good
Dec8Good
Location & terrain

Where is Altoona?

Altoona sits at 40.5°N, 78.4°W, 1,165 ft above sea level, in United States. The nearest listed city is Johnstown, 30 mi away.

Topography around Altoona

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

Within 2 miles, the terrain around Altoona has significant variations in elevation — a maximum elevation change of 942 ft around an average of 1,302 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,762 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,703 ft.

The land around Altoona is covered by trees (54%) and artificial surfaces (35%) within 2 miles, trees (80%) within 10 miles, and trees (80%) within 50 miles.

2 miles
942 ft
10 miles
1,762 ft
50 miles
2,703 ft
treesgrasslandcroplandartificial surfaces
September weather nearby: Johnstown 30 mi · State College 34 mi · Chambersburg 56 mi · Cumberland 63 mi · Carlisle 67 mi · Murrysville 69 mi · Hagerstown 70 mi · Plum 71 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 Altoona (40.5187°, -78.3947°, elevation 1,165 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).