Ottumwa weather in August

In August, Ottumwa sees average daytime highs of 83°F and overnight lows near 64°F, with 3.5 in of rain across 9.4 wet days and about 13.6 hours of daylight. It is the 2nd-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 83°F through the month. The sky is clear or mostly clear about 42% of the time in August, and the air most often feels muggy.

Daylight stretches from about 14 h 12 min at the start of August to 13 hours by month's end. Set against the rest of the year, August is Ottumwa's 2nd-clearest and 12th-windiest month. For the whole year in context, see Ottumwa's year-round climate.

Daytime high
83°
2nd warmest
Overnight low
64°
11th coldest
Rainfall
3.5 in
9.4 wet days
Daylight
13 h 42 min
5:24 AM – 7:03 PM
Cloud cover
50%
2nd clearest
Wind
7 mph
12th windiest
Solar energy
5.67 kWh/m²
Travel score
6.2
out of 10

Ottumwa is city in and the county seat of Wapello County, Iowa, United States.

Density
575/km²
people per km²
Founded
1844

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 83°F through the month.

A typical August day in Ottumwa reaches about 83°F in the afternoon and slips back to 64°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 75°F and 91°F. Set against its neighbours, August runs about 2°F cooler than July and about 7°F warmer than September.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18466
28466
38466
48465
58465
68465
78365
88365
98365
108365
118365
128364
138364
148364
158364
168364
178364
188364
198364
208364
218364
228364
238364
248264
258263
268263
278263
288263
298262
308262
318162

How August really feels in Ottumwa

Once humidity and wind are folded in, August 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

August sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Ottumwa weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan32° / 16°1.46.84.59.40.0
Feb36° / 20°1.874.310.40.0
Mar49° / 31°2.792.511.72.1
Apr62° / 42°4.311.60.813.14.9
May72° / 53°4.812.70.114.36.2
Jun81° / 63°5.011.8014.96.0
Jul85° / 67°3.39.6014.65.4
Aug83° / 64°3.59.4013.66.2
Sep76° / 56°3.68.1012.37.2
Oct64° / 44°2.87.90.210.95.9
Nov49° / 32°2.26.71.29.72.2
Dec37° / 22°1.86.33.59.10.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 42% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 18% of August, with mostly cloudy or overcast conditions the remaining 41%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16040
26040
36040
46040
56040
66040
76040
85941
95941
105941
115842
125842
135842
145842
155842
165842
175842
185842
195743
205743
215842
225842
235842
245842
256040
266040
276139
286238
296337
306337
316436

Chance of precipitation in August

Any precipitation

Ottumwa gets around 3.5 in of rain over 9.4 wet days in August. 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 31% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
129
229
329
429
529
629
730
830
930
1031
1131
1231
1331
1431
1531
1631
1731
1831
1931
2031
2131
2230
2330
2430
2529
2629
2728
2828
2928
3028
3128

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the muggy band about 29% of days. Sticky, muggy-or-worse air turns up on roughly 45% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
18182825191
28182926191
38182926191
48182926181
58172926181
69172926181
79172926171
89172926171
910162927171
1010162927171
1110162927161
1211152928161
1311152928161
1411152929161
1512152829151
1612152829151
1712152730150
1812162731150
1912162631140
2012162632140
2112162532140
2212172533140
2312172433140
2412182432140
2512192332130
2613192332130
2714202331130
2814202330120
2915212230120
3017212229110
3118222228100

Wind in August

Winds average 7 mph in August, the calmest month.

Across August, daily wind ranges from about 7 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 12 min at the start of August to 13 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 72 minutes over August. Sunrise moves from 5:09 AM to 5:40 AM, and sunset from 7:22 PM to 6:40 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.25:097:22
214.25:107:21
314.25:117:20
414.15:127:19
514.15:137:18
614.05:147:17
714.05:157:15
814.05:167:14
913.95:177:13
1013.95:187:12
1113.95:197:10
1213.85:207:09
1313.85:217:08
1413.75:227:06
1513.75:237:05
1613.75:247:03
1713.65:257:02
1813.65:267:00
1913.55:276:59
2013.55:286:57
2113.45:296:56
2213.45:306:54
2313.45:316:53
2413.35:326:51
2513.35:336:50
2613.25:346:48
2713.25:356:46
2813.15:366:45
2913.15:376:43
3013.05:396:41
3113.05:406:40

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.67 kWh/m².

For context, solar energy here swings from a low near 1.82 kWh/m² to a high of 6.44 kWh/m² in July across the year — August's 5.67 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.1Intense
26.1Intense
36.0Intense
46.0Intense
56.0Bright
66.0Bright
75.9Bright
85.9Bright
95.9Bright
105.8Bright
115.8Bright
125.8Bright
135.7Bright
145.7Bright
155.7Bright
165.7Bright
175.6Bright
185.6Bright
195.6Bright
205.6Bright
215.5Bright
225.5Bright
235.5Bright
245.5Bright
255.4Bright
265.4Bright
275.4Bright
285.4Bright
295.3Bright
305.3Bright
315.3Bright
Planning a trip in August

Is August a good time to visit Ottumwa?

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

6.2
Sightseeing
2nd-best month of the year
7.2
Beach & pool
1st-best month of the year

August is a reasonable time to visit Ottumwa for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Ottumwa in August

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

In August, Ottumwa sees daytime highs around 83°F and nights near 64°F. Pack light clothes. Worth having: rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

UV index in Ottumwa in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Ottumwa peaks around June 20 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 20UV 9Dec 19UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar4Moderate
Apr6High
May7Very high
Jun10Very high
Jul9Very high
Aug8Very high
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Ottumwa in August

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where August falls, not just the annual average.

Air quality in Ottumwa is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (October, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateGoodJul 1816 µg/m³Oct 217 µg/m³
PM2.5 (µg/m³)Level
Jan12Good
Feb14Moderate
Mar13Moderate
Apr11Good
May12Moderate
Jun13Moderate
Jul17Moderate
Aug14Moderate
Sep12Good
Oct7Good
Nov8Good
Dec10Good
Location & terrain

Where is Ottumwa?

Ottumwa sits at 41.0°N, 92.4°W, 673 ft above sea level, in United States. The nearest listed city is Newton, 57 mi away.

Topography around Ottumwa

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

Within 2 miles, the terrain around Ottumwa has only modest variations in elevation — a maximum elevation change of 249 ft around an average of 715 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 322 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 574 ft.

The land around Ottumwa is covered by trees (45%), artificial surfaces (25%) and grassland (20%) within 2 miles, cropland (40%), trees (33%) and grassland (24%) within 10 miles, and cropland (52%), grassland (25%) and trees (22%) within 50 miles.

2 miles
249 ft
10 miles
322 ft
50 miles
574 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Newton 57 mi · Kirksville 58 mi · Coralville 63 mi · Iowa City 63 mi · Indianola 64 mi · North Liberty 66 mi · Burlington 70 mi · Altoona 70 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 Ottumwa (41.02°, -92.4113°, elevation 673 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).