Indianapolis weather in August: Indianapolis, Indiana: normal highs, lows, rain and records for August
Indianapolis in August has a normal high of 84°F and a normal low of 65°F, a daily mean of 75°F, falling from 85°F on the 1st to 83°F by the 31st. Measurable precipitation falls on 8 days in a normal August, 3.20 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 29°C and low of 18°C, 81 mm of precipitation in August.
- NOAA stationIndianapolis International Airport
- Station IDUSW00093819
- Location39.71°N 86.28°W
- Elevation790 ft (241 m)
- From the center9 miles
- Population891,484
- Jan 36° 21°
- Feb 41° 24°
- Mar 52° 33°
- Apr 64° 43°
- May 73° 54°
- Jun 82° 63°
- Jul 85° 66°
- Aug 84° 65°
- Sep 78° 57°
- Oct 66° 46°
- Nov 52° 35°
- Dec 40° 26°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Indianapolis in August?
The normal high is 84°F and the normal low 65°F, for a daily mean of 74.7°F. August is 1.1°F cooler than July and 6.9°F warmer than September. August is the 2nd warmest month of the year in Indianapolis and the 8th wettest. Across the month the normal high falls 2°F, from 85°F on August 1 to 83°F on August 31. From one year to the next August's mean temperature typically moves about 2.5°F either way (NOAA's standard deviation), so roughly two Augusts in three average between 72°F and 77°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 30%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| August 1 | 85°F | 66°F | 30% | 19% |
| August 8 | 85°F | 66°F | 29% | 19% |
| August 15 | 85°F | 65°F | 28% | 18% |
| August 22 | 84°F | 65°F | 26% | 17% |
| August 31 | 83°F | 63°F | 26% | 16% |
Every day of August: normal high, low and chance of precipitation (warmest afternoon August 1, coldest night August 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| August 1 | 85°F | 66°F | 30% | 19% | 14 h 20 min |
| August 2 | 85°F | 66°F | 30% | 19% | 14 h 10 min |
| August 3 | 85°F | 66°F | 30% | 19% | 14 h 10 min |
| August 4 | 85°F | 66°F | 29% | 19% | 14 h 10 min |
| August 5 | 85°F | 66°F | 29% | 19% | 14 h 10 min |
| August 6 | 85°F | 66°F | 29% | 19% | 14 h 10 min |
| August 7 | 85°F | 66°F | 29% | 19% | 14 h |
| August 8 | 85°F | 66°F | 29% | 19% | 14 h |
| August 9 | 85°F | 66°F | 29% | 19% | 14 h |
| August 10 | 85°F | 66°F | 28% | 18% | 14 h |
| August 11 | 85°F | 66°F | 28% | 18% | 14 h |
| August 12 | 85°F | 66°F | 28% | 18% | 13 h 50 min |
| August 13 | 85°F | 66°F | 28% | 18% | 13 h 50 min |
| August 14 | 85°F | 66°F | 28% | 18% | 13 h 50 min |
| August 15 | 85°F | 65°F | 28% | 18% | 13 h 50 min |
| August 16 | 85°F | 65°F | 27% | 18% | 13 h 40 min |
| August 17 | 85°F | 65°F | 27% | 18% | 13 h 40 min |
| August 18 | 84°F | 65°F | 27% | 18% | 13 h 40 min |
| August 19 | 84°F | 65°F | 27% | 18% | 13 h 40 min |
| August 20 | 84°F | 65°F | 27% | 17% | 13 h 40 min |
| August 21 | 84°F | 65°F | 27% | 17% | 13 h 30 min |
| August 22 | 84°F | 65°F | 26% | 17% | 13 h 30 min |
| August 23 | 84°F | 64°F | 26% | 17% | 13 h 30 min |
| August 24 | 84°F | 64°F | 26% | 17% | 13 h 30 min |
| August 25 | 84°F | 64°F | 26% | 17% | 13 h 20 min |
| August 26 | 84°F | 64°F | 26% | 17% | 13 h 20 min |
| August 27 | 84°F | 64°F | 26% | 17% | 13 h 20 min |
| August 28 | 83°F | 64°F | 26% | 17% | 13 h 20 min |
| August 29 | 83°F | 63°F | 26% | 17% | 13 h 10 min |
| August 30 | 83°F | 63°F | 26% | 16% | 13 h 10 min |
| August 31 | 83°F | 63°F | 26% | 16% | 13 h 10 min |
- Normal high
- 84°FAugust average
- Normal low
- 65°FAugust average
- Precipitation
- 3.20 inmonth total
- Days with precipitation
- 80.01 inch or more
- Days at 90°F or more
- 6
- Daylight
- 14 h 20 min to 13 h 10 minAugust 1 to August 31
- Days at 70°F or more
- 31
- Days at 80°F or more
- 25
- Sunshine
- 81%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00093819; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Indianapolis in August?
On a given August day the chance of 0.01 inch or more is 27% on average, highest around August 1 (30%). In all, 3.20 in falls on 8 days of a normal August, 1 of them with an inch or more.
In a normal August in Indianapolis, 6 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00093819.
How humid and windy is Indianapolis in August?
At 3 p.m. the normal temperature is 82°F with 51% relative humidity and a dew point of 62°F; at 6 a.m. it is 65°F with 87% humidity. The wind averages 7.5 mph, most often from the west-southwest in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 65°F | 61°F | 87% | 5.5 mph | 49% |
| 9 a.m. | 72°F | 63°F | 74% | 7.2 mph | 47% |
| noon | 79°F | 63°F | 57% | 8.9 mph | 36% |
| 3 p.m. | 82°F | 62°F | 51% | 9.8 mph | 26% |
| 6 p.m. | 80°F | 62°F | 55% | 9.5 mph | 30% |
| 9 p.m. | 73°F | 62°F | 69% | 6.9 mph | 49% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00093819. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for August in Indianapolis?
The warmest August temperature on Indianapolis's official record (since 1871) is 103°F, on August 5, 1918; the coldest is 41°F, on August 29, 1965. The wettest August brought 8.34 in (1980).
The August mean against the 1991-2020 normal of 74.7°F: 2021 77.5°F (+2.8), 2022 75.0°F (+0.3), 2023 74.5°F (−0.3), 2024 75.3°F (+0.6), 2025 73.8°F (−0.9), 2026 75.4°F (+0.7). 4 of 6 ran warmer than normal.
| August | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 77.5°F | +2.8°F | 1.99 in |
| 2022 | 75.0°F | +0.3°F | 4.44 in |
| 2023 | 74.5°F | −0.3°F | 2.97 in |
| 2024 | 75.3°F | +0.6°F | 2.10 in |
| 2025 | 73.8°F | −0.9°F | 1.31 in |
| 2026 | 75.4°F | +0.7°F | 7.33 in |
Source: records: ACIS, NWS threaded record INDthr; recent months: ACIS, station USW00093819. Records and recent months use complete months only.
How does August in Indianapolis compare across Indiana?
Across the 99 places PlainClimate covers in Indiana, August normal highs run from 80°F in Angola to 88°F in English; Indianapolis's is 84°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.