Aberdeen weather in September

In September, Aberdeen sees average daytime highs of 73°F and overnight lows near 50°F, with 2.5 in of rain across 7.1 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 78°F in the first days to 67°F by the end. The sky is clear or mostly clear about 48% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 06 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Aberdeen's 3rd-clearest and 6th-windiest month. For the whole year in context, see Aberdeen's year-round climate.

Daytime high
73°
4th warmest
Overnight low
50°
9th coldest
Rainfall
2.5 in
7.1 wet days
Daylight
12 h 18 min
6:19 AM – 6:38 PM
Cloud cover
45%
3rd clearest
Wind
9 mph
6th windiest
Solar energy
4.42 kWh/m²
Travel score
7.3
out of 10

Aberdeen is city in and the county seat of Brown County, South Dakota, United States.

Density
680/km²
people per km²
Founded
1880

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 78°F in the first days to 67°F by the end.

A typical September day in Aberdeen reaches about 73°F in the afternoon and slips back to 50°F overnight — a 23°F spread between the day's warmth and the night's chill. On most days the high lands between 59°F and 85°F. Set against its neighbours, September runs about 8°F cooler than August and about 15°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17956
27856
37856
47855
57755
67754
77654
87653
97553
107553
117452
127452
137451
147351
157350
167250
177249
187149
197148
207148
217047
227047
236946
246946
256846
266845
276745
286744
296744
306644

How September really feels in Aberdeen

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.

Aberdeen weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan22° / 0.74.24.58.90.0
Feb27° / 0.84.34.310.10.0
Mar40° / 21°1.45.93.511.60.5
Apr55° / 33°2.382.213.23.6
May68° / 47°3.410.50.114.76.1
Jun77° / 57°4.211.5015.46.6
Jul83° / 62°2.98.7015.16.4
Aug81° / 59°2.97.9013.97.1
Sep73° / 50°2.57.1012.37.3
Oct58° / 37°2.06.70.910.74.6
Nov41° / 23°1.04.43.39.30.5
Dec27° / 11°0.84.44.78.60.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 48% 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 37%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17030
27030
36931
46931
56931
66832
76733
86634
96535
106535
116436
126337
136238
146238
156139
166139
176139
186139
196139
206238
216139
226139
236139
246238
256139
266139
276040
286040
296040
305941

Chance of precipitation in September

Any precipitation

Aberdeen gets around 2.5 in of rain over 7.1 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 24% and peaks near 25% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
123
223
323
423
523
623
723
823
923
1023
1124
1224
1324
1424
1525
1625
1725
1825
1925
2025
2125
2224
2324
2424
2524
2624
2724
2824
2924
3024

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 72% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
143232310
24523229
34822218
45022217
55222206
65421196
75621185
85920174
96020164
106319153
116518143
126618133
136917122
147116112
157216102
16741592
17771481
18791371
19811261
20831151
21831151
22851041
2387931
2489830
2590820
2691720
2792620
2893610
2993610
3094510

Wind in September

Winds average 9 mph in September.

Across September, daily wind ranges from about 9 mph on the calmest days to 10 mph at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (mph)Feels
19light breeze
29light breeze
39light breeze
49light breeze
59light breeze
69light breeze
79light breeze
89light breeze
99light breeze
109light breeze
119light breeze
129light breeze
139light breeze
149light breeze
159light breeze
169light breeze
179light breeze
189light breeze
199light breeze
209light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
2710light breeze
2810light breeze
2910light breeze
3010light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 96 minutes over September. Sunrise moves from 6:00 AM to 6:37 AM, and sunset from 7:07 PM to 6:10 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.16:007:07
213.16:017:05
313.06:027:03
413.06:047:02
512.96:057:00
612.96:066:58
712.86:086:56
812.76:096:54
912.76:106:52
1012.66:116:50
1112.66:136:48
1212.56:146:46
1312.56:156:44
1412.46:166:42
1512.46:186:40
1612.36:196:38
1712.36:206:36
1812.26:216:34
1912.26:236:32
2012.16:246:30
2112.06:256:28
2212.06:266:26
2311.96:286:24
2411.96:296:22
2511.86:306:20
2611.86:326:18
2711.76:336:16
2811.76:346:14
2911.66:356:12
3011.56:376:10

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.42 kWh/m².

For context, solar energy here swings from a low near 1.53 kWh/m² to a high of 6.69 kWh/m² in July across the year — September's 4.42 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.2Bright
35.1Bright
45.0Bright
55.0Bright
64.9Bright
74.9Bright
84.8Bright
94.7Bright
104.7Bright
114.6Bright
124.6Bright
134.5Bright
144.5Bright
154.4Bright
164.3Bright
174.3Bright
184.2Bright
194.2Bright
204.2Bright
214.1Bright
224.1Bright
234.0Bright
244.0Moderate
253.9Moderate
263.9Moderate
273.8Moderate
283.8Moderate
293.7Moderate
303.7Moderate
Planning a trip in September

Hazard calendar for Aberdeen

In seasonPeak

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

Aberdeen's rainy season runs April–October, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Aberdeen?

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

7.3
Sightseeing
1st-best month of the year
5.2
Beach & pool
4th-best month of the year

September is one of the better times to visit Aberdeen for general sightseeing.

What to pack for Aberdeen in September

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

In September, Aberdeen sees daytime highs around 73°F and nights near 50°F. Worth packing: light clothes. About 7 days see rain.

light clothes

UV index in Aberdeen in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Aberdeen peaks around June 20 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 20UV 9Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar3Moderate
Apr5Moderate
May6High
Jun9Very high
Jul8Very high
Aug7High
Sep5High
Oct4Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Aberdeen?

Aberdeen sits at 45.5°N, 98.5°W, 1,302 ft above sea level, in United States. The nearest listed city is Watertown, 78 mi away.

Topography around Aberdeen

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

Within 2 miles, the terrain around Aberdeen has only modest variations in elevation — a maximum elevation change of 43 ft around an average of 1,306 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 161 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 981 ft.

The land around Aberdeen is covered by grassland (34%) and artificial surfaces (31%) within 2 miles, cropland (67%) and grassland (27%) within 10 miles, and cropland (62%) and grassland (35%) within 50 miles.

2 miles
43 ft
10 miles
161 ft
50 miles
981 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Watertown 78 mi · Jamestown 101 mi · Brookings 115 mi · Mitchell 124 mi · West Fargo 124 mi · Fargo 127 mi · Moorhead 127 mi · Bismarck 144 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 Aberdeen (45.4647°, -98.4865°, elevation 1,302 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).