Indianapolis weather in August

In August, Indianapolis sees average daytime highs of 83°F and overnight lows near 65°F, with 2.8 in of rain across 9 wet days and about 13.6 hours of daylight. It is the 2nd-warmest and 11th-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 38% of the time in August, and the air most often feels muggy.

Daylight stretches from about 14 h 06 min at the start of August to 13 hours by month's end. Set against the rest of the year, August is Indianapolis's 2nd-clearest and 12th-windiest month. For the whole year in context, see Indianapolis's year-round climate.

Daytime high
83°
2nd warmest
Overnight low
65°
11th coldest
Rainfall
2.8 in
9 wet days
Daylight
13 h 36 min
6:01 AM – 7:36 PM
Cloud cover
53%
2nd clearest
Wind
6 mph
12th windiest
Solar energy
5.65 kWh/m²
Travel score
6.2
out of 10

Indianapolis is capital city of the U.S. state of Indiana and seat of Marion County.

Density
931/km²
people per km²
Founded
1821

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 Indianapolis reaches about 83°F in the afternoon and slips back to 65°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 75°F and 90°F. Set against its neighbours, August runs on par with July and about 6°F warmer than September.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18366
28366
38366
48366
58366
68366
78366
88366
98365
108365
118365
128365
138365
148365
158365
168365
178265
188265
198265
208265
218265
228265
238264
248264
258264
268264
278264
288264
298264
308263
318263

How August really feels in Indianapolis

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.

Indianapolis weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan36° / 22°3.29.24.29.50.0
Feb40° / 25°2.68.5410.40.2
Mar51° / 33°3.811.1211.72.4
Apr63° / 44°4.7120.4135.1
May72° / 55°4.813.4014.26.1
Jun81° / 64°4.211.8014.86.0
Jul84° / 67°3.611.5014.55.4
Aug83° / 65°2.89013.66.2
Sep77° / 57°2.87.6012.37.2
Oct64° / 46°3.38.50.110.96.0
Nov51° / 35°3.48.80.89.82.5
Dec40° / 27°3.19.83.59.20.1

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% 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 43%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15743
25743
35743
45743
55743
65644
75644
85644
95644
105545
115545
125545
135545
145644
155644
165644
175743
185743
195743
205743
215743
225743
235743
245743
255743
265743
275842
285842
295842
305941
315941

Chance of precipitation in August

Any precipitation

Indianapolis gets around 2.8 in of rain over 9 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 29% and peaks near 32% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
132
232
331
431
530
630
730
829
929
1029
1129
1229
1329
1429
1529
1628
1728
1828
1928
2028
2128
2228
2328
2428
2528
2628
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 27% of days. Sticky, muggy-or-worse air turns up on roughly 43% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
18212526200
28212526190
38222526190
49222526181
59222526181
69222426171
710222426171
810222426171
911222426161
1011222327161
1111212327161
1211212327161
1312212327151
1411222328151
1511222328141
1611222328141
1711222429131
1811222429131
1911222429131
2011212429131
2111212529131
2211212529131
2312212529131
2412202529130
2513202529130
2614202529120
2715202528120
2816202428120
2917202427110
3018202427110
3120202426100

Wind in August

Winds average 6 mph in August, the calmest month.

Across August, 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.

0246810151015202531
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
316calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 06 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 66 minutes over August. Sunrise moves from 5:47 AM to 6:16 AM, and sunset from 7:54 PM to 7:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.15:477:54
214.15:487:53
314.15:497:52
414.05:507:51
514.05:517:50
614.05:527:49
713.95:537:48
813.95:547:46
913.85:557:45
1013.85:567:44
1113.85:577:43
1213.75:577:41
1313.75:587:40
1413.75:597:39
1513.66:007:37
1613.66:017:36
1713.56:027:35
1813.56:037:33
1913.56:047:32
2013.46:057:30
2113.46:067:29
2213.36:077:28
2313.36:087:26
2413.36:097:24
2513.26:107:23
2613.26:117:21
2713.16:127:20
2813.16:137:18
2913.06:147:17
3013.06:157:15
3113.06:167:13

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.65 kWh/m².

For context, solar energy here swings from a low near 1.7 kWh/m² to a high of 6.26 kWh/m² in June across the year — August's 5.65 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.0Intense
26.0Bright
36.0Bright
46.0Bright
55.9Bright
65.9Bright
75.9Bright
85.8Bright
95.8Bright
105.8Bright
115.8Bright
125.7Bright
135.7Bright
145.7Bright
155.7Bright
165.6Bright
175.6Bright
185.6Bright
195.6Bright
205.5Bright
215.5Bright
225.5Bright
235.5Bright
245.4Bright
255.4Bright
265.3Bright
275.3Bright
285.3Bright
295.2Bright
305.2Bright
315.2Bright
Planning a trip in August

Is August a good time to visit Indianapolis?

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
7.1
Beach & pool
1st-best month of the year

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

What to pack for Indianapolis in August

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

In August, Indianapolis sees daytime highs around 83°F and nights near 65°F. Pack light clothes. Worth having: rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

UV index in Indianapolis 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 Indianapolis peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 highHighModerateJun 23UV 9Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Indianapolis 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 Indianapolis is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodJul 1416 µg/m³Oct 218 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb12Moderate
Mar12Moderate
Apr12Good
May14Moderate
Jun16Moderate
Jul17Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Indianapolis?

Indianapolis sits at 39.8°N, 86.2°W, 715 ft above sea level, in United States. The nearest listed city is Broad Ripple, 6.8 mi away.

Topography around Indianapolis

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

Within 2 miles, the terrain around Indianapolis has only modest variations in elevation — a maximum elevation change of 128 ft around an average of 719 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 515 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 761 ft.

The land around Indianapolis is covered by artificial surfaces (71%) within 2 miles, trees (43%), artificial surfaces (30%) and grassland (20%) within 10 miles, and cropland (58%) and trees (29%) within 50 miles.

2 miles
128 ft
10 miles
515 ft
50 miles
761 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Broad Ripple 6.8 mi · Lawrence 8.7 mi · Greenwood 11 mi · Fairfield Heights 12 mi · Avon 13 mi · Plainfield 14 mi · Brownsburg 14 mi · Zionsville 14 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 Indianapolis (39.7684°, -86.158°, elevation 715 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).