Rolla weather in September

In September, Rolla sees average daytime highs of 79°F and overnight lows near 59°F, with 3.3 in of rain across 7.9 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 84°F in the first days to 75°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 12 h 54 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Rolla's 1st-clearest and 10th-windiest month. For the whole year in context, see Rolla's year-round climate.

Daytime high
79°
4th warmest
Overnight low
59°
9th coldest
Rainfall
3.3 in
7.9 wet days
Daylight
12 h 12 min
5:54 AM – 6:09 PM
Cloud cover
46%
1st clearest
Wind
6 mph
10th windiest
Solar energy
4.76 kWh/m²
Travel score
7.0
out of 10

Rolla is city in and county seat of Phelps County, Missouri, United States.

Density
641/km²
people per km²
Founded
1844

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 84°F in the first days to 75°F by the end.

A typical September day in Rolla reaches about 79°F in the afternoon and slips back to 59°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 69°F and 89°F. Set against its neighbours, September runs about 7°F cooler than August and about 11°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18464
28464
38464
48363
58363
68262
78262
88262
98161
108161
118060
128060
138060
147959
157959
167958
177858
187858
197857
207757
217756
227756
237656
247655
257655
267655
277554
287554
297553
307453

How September really feels in Rolla

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.

Rolla weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan42° / 25°2.77.63.19.70.1
Feb46° / 28°2.57.62.610.51.4
Mar56° / 37°3.610.81.611.73.8
Apr67° / 47°4.811.80.2135.8
May74° / 56°5.013.30146.3
Jun83° / 65°3.811.3014.65.5
Jul88° / 69°3.510.7014.44.5
Aug86° / 67°2.99.5013.55.0
Sep79° / 59°3.37.9012.37.0
Oct68° / 47°3.38.70.1116.6
Nov55° / 37°3.48.20.99.93.7
Dec45° / 29°2.67.72.19.40.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 48% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 38%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16238
26238
36238
46238
56238
66238
76238
86238
96139
106238
116238
126139
136139
146040
156040
166040
176040
186040
196040
206040
216139
226139
236238
246436
256535
266535
276634
286634
296733
306733

Chance of precipitation in September

Any precipitation

Rolla gets around 3.3 in of rain over 7.9 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 27% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
127
227
327
427
527
627
727
827
927
1027
1127
1227
1328
1428
1528
1628
1729
1829
1928
2028
2128
2227
2327
2426
2525
2625
2724
2824
2924
3023

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 35% of days. Sticky, muggy-or-worse air turns up on roughly 26% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
11117223713
21218223612
31419223411
41520223310
5172122319
6182122309
7202222288
8222322277
9232321266
10252321256
11272321245
12282321234
13302320234
14322320223
15332320213
16352219212
17372219202
18382219192
19402218191
20422118181
21442117171
22462117161
23482016151
24502015150
25512015140
26541914130
27551914120
28571913110
29591813100
30601812100

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
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 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 72 minutes over September. Sunrise moves from 5:41 AM to 6:07 AM, and sunset from 6:33 PM to 5:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:416:33
212.85:426:31
312.85:436:29
412.75:446:28
512.75:456:26
612.75:456:25
712.65:466:23
812.65:476:22
912.55:486:20
1012.55:496:18
1112.45:506:17
1212.45:516:15
1312.45:526:14
1412.35:526:12
1512.35:536:10
1612.25:546:09
1712.25:556:07
1812.25:566:05
1912.15:576:04
2012.15:586:02
2112.05:596:00
2212.06:005:59
2311.96:005:57
2411.96:015:56
2511.96:025:54
2611.86:035:52
2711.86:045:51
2811.76:055:49
2911.76:065:48
3011.76:075:46

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.76 kWh/m².

For context, solar energy here swings from a low near 2.01 kWh/m² to a high of 6.41 kWh/m² in June across the year — September's 4.76 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.2Bright
35.2Bright
45.1Bright
55.1Bright
65.1Bright
75.0Bright
85.0Bright
95.0Bright
104.9Bright
114.9Bright
124.8Bright
134.8Bright
144.8Bright
154.7Bright
164.7Bright
174.7Bright
184.6Bright
194.6Bright
204.6Bright
214.5Bright
224.5Bright
234.5Bright
244.5Bright
254.5Bright
264.5Bright
274.4Bright
284.4Bright
294.4Bright
304.3Bright
Planning a trip in September

Is September a good time to visit Rolla?

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

7.0
Sightseeing
1st-best month of the year
6.8
Beach & pool
2nd-best month of the year

September is one of the better times to visit Rolla for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Rolla in September

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

In September, Rolla sees daytime highs around 79°F and nights near 59°F. Worth packing: light clothes and sun protection. About 8 days see rain.

light clothessun protection

UV index in Rolla in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Rolla peaks around June 22 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 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 22UV 10Dec 23UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5High
Apr7Very high
May8Very high
Jun10Very high
Jul10Very high
Aug9Very high
Sep7High
Oct4Moderate
Nov4Moderate
Dec2Moderate

Air quality in Rolla 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 Rolla is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.8× the cleanest month (November, 6 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1516 µg/m³Nov 146 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb10Good
Mar11Good
Apr9Good
May12Moderate
Jun14Moderate
Jul16Moderate
Aug13Moderate
Sep11Good
Oct6Good
Nov6Good
Dec7Good
Location & terrain

Where is Rolla?

Rolla sits at 38.0°N, 91.8°W, 1,122 ft above sea level, in United States. The nearest listed city is Fort Leonard Wood, 27 mi away.

Topography around Rolla

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

Within 2 miles, the terrain around Rolla has only modest variations in elevation — a maximum elevation change of 308 ft around an average of 1,073 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 633 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,060 ft.

The land around Rolla is covered by trees (55%) and artificial surfaces (24%) within 2 miles, trees (66%) and grassland (30%) within 10 miles, and trees (73%) and grassland (23%) within 50 miles.

2 miles
308 ft
10 miles
633 ft
50 miles
1,060 ft
treesgrasslandcroplandartificial surfacesbare terrain
September weather nearby: Fort Leonard Wood 27 mi · Jefferson City 48 mi · Wildwood 75 mi · Farmington 75 mi · Columbia 76 mi · Wentzville 78 mi · Ballwin 80 mi · Chesterfield 81 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 Rolla (37.9514°, -91.7713°, elevation 1,122 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).