Fort Smith weather in September

In September, Fort Smith sees average daytime highs of 83°F and overnight lows near 64°F, with 3.7 in of rain across 7.4 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 88°F in the first days to 80°F by the end. The sky is clear or mostly clear about 51% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Fort Smith's 1st-clearest and 10th-windiest month. For the whole year in context, see Fort Smith's year-round climate.

Daytime high
83°
4th warmest
Overnight low
64°
9th coldest
Rainfall
3.7 in
7.4 wet days
Daylight
12 h 12 min
6:05 AM – 6:19 PM
Cloud cover
42%
1st clearest
Wind
5 mph
10th windiest
Solar energy
4.99 kWh/m²
Travel score
6.2
out of 10

Fort Smith is city in and county seat of Sebastian County, Arkansas, United States.

Density
500/km²
people per km²
Founded
1817

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 88°F in the first days to 80°F by the end.

A typical September day in Fort Smith reaches about 83°F in the afternoon and slips back to 64°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 74°F and 92°F. Set against its neighbours, September runs about 7°F cooler than August and about 11°F warmer than October.

40°60°80°100°151015202530
Avg high (°F)Avg low (°F)
18969
28868
38868
48868
58767
68767
78767
88666
98666
108566
118565
128565
138465
148464
158364
168364
178363
188363
198262
208262
218262
228161
238161
248160
258060
268059
278059
288058
297958
307958

How September really feels in Fort Smith

Once humidity and wind are folded in, September averages 3 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
3
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Fort Smith weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan49° / 31°3.38.91.19.92.1
Feb54° / 35°3.38.40.910.73.3
Mar62° / 43°4.911.30.711.75.3
Apr71° / 51°5.911.3012.96.4
May78° / 60°5.812.9013.86.3
Jun86° / 69°3.610.4014.34.9
Jul91° / 72°3.18.8014.13.8
Aug91° / 71°2.58.3013.34.0
Sep83° / 64°3.77.4012.26.2
Oct73° / 52°4.29011.17.1
Nov60° / 42°4.38.70.210.15.2
Dec51° / 34°3.88.90.99.72.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 51% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 33%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16832
26832
36733
46832
56733
66733
76634
86535
96535
106535
116535
126535
136535
146436
156436
166436
176436
186436
196535
206535
216634
226733
236832
246931
257030
267030
277129
287129
297228
307228

Chance of precipitation in September

Any precipitation

Fort Smith gets around 3.7 in of rain over 7.4 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 25% and peaks near 27% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
125
225
325
425
525
625
726
826
926
1026
1126
1226
1327
1427
1527
1627
1727
1827
1926
2026
2125
2225
2324
2423
2522
2621
2721
2821
2920
3020

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 29% of days. Sticky, muggy-or-worse air turns up on roughly 40% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
169213924
2710223923
3810223822
4911223821
51012223720
61113223618
71214223517
81314223516
91415213515
101515213414
111615213413
121716213412
131816213411
141916213310
152016223210
16221622319
17231622318
18241722308
19261722297
20271722276
21291722266
22311722256
23331721235
24351721225
25371820205
26391820194
27411819184
28431818174
29441918163
30461917153

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
225calm
235calm
245calm
255calm
265calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 48 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 66 minutes over September. Sunrise moves from 5:54 AM to 6:16 AM, and sunset from 6:41 PM to 5:57 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:546:41
212.75:556:39
312.75:556:38
412.75:566:36
512.65:576:35
612.65:586:34
712.65:586:32
812.55:596:31
912.56:006:29
1012.46:016:28
1112.46:016:26
1212.46:026:25
1312.36:036:23
1412.36:046:22
1512.36:056:20
1612.26:056:19
1712.26:066:17
1812.16:076:15
1912.16:086:14
2012.16:086:12
2112.06:096:11
2212.06:106:09
2312.06:116:08
2411.96:126:06
2511.96:126:05
2611.86:136:03
2711.86:146:02
2811.86:156:00
2911.76:165:59
3011.76:165:57

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.99 kWh/m².

For context, solar energy here swings from a low near 2.27 kWh/m² to a high of 6.58 kWh/m² in July across the year — September's 4.99 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.4Bright
45.4Bright
55.4Bright
65.3Bright
75.3Bright
85.2Bright
95.2Bright
105.1Bright
115.1Bright
125.0Bright
135.0Bright
145.0Bright
154.9Bright
164.9Bright
174.9Bright
184.8Bright
194.8Bright
204.8Bright
214.8Bright
224.8Bright
234.8Bright
244.8Bright
254.7Bright
264.7Bright
274.7Bright
284.7Bright
294.6Bright
304.6Bright
Planning a trip in September

Is September a good time to visit Fort Smith?

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

6.2
Sightseeing
4th-best month of the year
7.3
Beach & pool
1st-best month of the year

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

What to pack for Fort Smith in September

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

In September, Fort Smith sees daytime highs around 83°F and nights near 64°F. Pack light clothes. Worth having: sun protection. About 7 days see rain.

light clothessun protection

UV index in Fort Smith in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Fort Smith peaks around June 23 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJun 23UV 10Dec 21UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr8Very high
May8Very high
Jun10Very high
Jul10Very high
Aug9Very high
Sep8Very high
Oct5High
Nov4Moderate
Dec2Moderate

Air quality in Fort Smith 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 Fort Smith is worst in July — around 20 µg/m³ PM2.5 (moderate), about 3.0× the cleanest month (December, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodJul 1519 µg/m³Dec 137 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb12Good
Mar15Moderate
Apr11Good
May13Moderate
Jun17Moderate
Jul20Moderate
Aug16Moderate
Sep12Good
Oct8Good
Nov7Good
Dec7Good
Location & terrain

Where is Fort Smith?

Fort Smith sits at 35.4°N, 94.4°W, 440 ft above sea level, in United States. The nearest listed city is Van Buren, 4.3 mi away.

Topography around Fort Smith

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

Within 2 miles, the terrain around Fort Smith has only modest variations in elevation — a maximum elevation change of 256 ft around an average of 472 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 745 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,411 ft.

The land around Fort Smith is covered by trees (47%) and artificial surfaces (36%) within 2 miles, trees (48%) and grassland (25%) within 10 miles, and trees (67%) and grassland (27%) within 50 miles.

2 miles
256 ft
10 miles
745 ft
50 miles
2,411 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Van Buren 4.3 mi · Tahlequah 48 mi · Fayetteville 48 mi · Siloam Springs 56 mi · Springdale 57 mi · Muskogee 60 mi · Rogers 67 mi · Bentonville 69 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 Fort Smith (35.3859°, -94.3986°, elevation 440 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).