Indianapolis, IN Climate & Monthly Averages
Indianapolis has a humid subtropical climate. July is the hottest month, averaging 85° by day; January is the coldest at 38°.
Indianapolis's climate is a story of contrasts
Indianapolis runs one of the wider annual swings in our dataset: 25°C separates the average July from the average January. Afternoons reach 85°F (29°C) at the peak of summer and 38°F (3°C) at the depth of winter, with 130 days of measurable precipitation through the year.
July
85° by day 67° at nightJanuary
38° by day 23° at nightThe two ends of the year
The wettest month is March (5.3 inches (135 mm) across 13 days) and the driest September. July is the warm end of the year, averaging 85°F (29°C) by day and 67°F (20°C) overnight. January is the coolest month, with highs of 38°F (3°C) and lows near 23°F (-5°C). Across the gridded 2015-2024 daily record, the highest daily maximum for this location was 95°F (35°C) and the lowest daily minimum -18°F (-28°C).
Snow falls on roughly 10 days a year, mostly November through April.
Overnight lows average at or below freezing for 3 months, December through February. Between the average July and the average January lie 25°C, a wider spread than roughly 85% of the cities we track.
More climate facts for Indianapolis
- Hottest month: July - highs near 85°F (29°C)
- Coldest month: January - highs near 38°F (3°C)
- Decade extremes (2015-2024): 95°F (35°C) high · -18°F (-28°C) low
- Wettest month: March (13 rainy days) · Sunniest: July (11.7 h sun/day)
- Climate type: humid subtropical
- Annual swing: 25°C between the average warmest and coolest month · day to night: 10°C
- Snow: about 10 days a year
- Months with freezing average lows: 3
- Average humidity: 70%
Four distinct parts of the year in Indianapolis
Spring (March through May)
Spring stays on the cool side of mild here - highs near 63°F (17°C), nights near 44°F (7°C), and rain falls on around 39 of the 90 days.
Summer (June through August)
Summer in Indianapolis runs hot, with daytime highs averaging 83°F (29°C) and nights around 66°F (19°C); rain falls on around 36 of the 90 days. Daylight is generous - around 11.5 hours of sun a day. With the moisture factored in, afternoons feel hotter than the reading suggests - the humidity and dew point converter shows why.
Fall (September through November)
Through fall, Indianapolis is mild: 66°F (19°C) by day, 49°F (9°C) after dark, and expect showers on roughly 26 days across the season.
Winter (December through February)
Winter stays firmly cold here - highs near 41°F (5°C), nights near 26°F (-4°C), and expect showers on roughly 29 days across the season, plus about 8 snowy days.
Indianapolis temperature extremes in the 2015–2024 dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.
Choosing a season in Indianapolis
Best time to visit Indianapolis
August to October and June is the sweet spot for Indianapolis - warm days, manageable rainfall and plenty of daylight line up. Expect 78°F (25°C) in the afternoon and around 10 days of rain in a typical month of it. For the same question asked the other way round, see where else is warm in August.
What to pack
Pack for Indianapolis with light clothing for the warm months, a heavy insulated coat, hat and gloves for winter and a compact umbrella or rain shell. July nights average 67°F (20°C), so evenings rarely match the afternoons.
Monthly highs, lows and seasonal change
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 38° | 23° | 10 | 3.4 in | 5.1 h/day | 9.6 h | 34% | 72% |
| February | 43° | 25° | 9 | 3.2 in | 6.6 h/day | 10.6 h | 32% | 69% |
| March | 52° | 34° | 13 | 5.3 in | 7.4 h/day | 11.8 h | 41% | 68% |
| April | 62° | 43° | 12 | 4.1 in | 8.7 h/day | 13.2 h | 41% | 66% |
| May | 73° | 55° | 14 | 4.9 in | 9.9 h/day | 14.4 h | 46% | 70% |
| June | 82° | 64° | 12 | 4.0 in | 11.6 h/day | 15.0 h | 38% | 67% |
| July | 85° | 67° | 13 | 4.6 in | 11.7 h/day | 14.7 h | 41% | 73% |
| August | 83° | 66° | 11 | 3.5 in | 11.3 h/day | 13.7 h | 36% | 72% |
| September | 79° | 61° | 7 | 2.9 in | 10.0 h/day | 12.4 h | 25% | 69% |
| October | 66° | 49° | 10 | 3.1 in | 8.0 h/day | 11.1 h | 31% | 69% |
| November | 52° | 36° | 9 | 3.2 in | 6.4 h/day | 9.9 h | 30% | 71% |
| December | 44° | 29° | 9 | 3.5 in | 5.1 h/day | 9.4 h | 30% | 74% |
Indianapolis from the coldest month to the hottest
Each card shows the average high and low. The bar places that month between Indianapolis's coldest night and warmest afternoon.
January
- Rain
- 10 days
- Sunshine
- 5.1 h
- Daylight
- 9.6 h
- Snow
- 3 days
February
- Rain
- 9 days
- Sunshine
- 6.6 h
- Daylight
- 10.6 h
- Snow
- 3 days
March
- Rain
- 13 days
- Sunshine
- 7.4 h
- Daylight
- 11.8 h
- Snow
- 1 day
April
- Rain
- 12 days
- Sunshine
- 8.7 h
- Daylight
- 13.2 h
May
- Rain
- 14 days
- Sunshine
- 9.9 h
- Daylight
- 14.4 h
June
- Rain
- 12 days
- Sunshine
- 11.6 h
- Daylight
- 15.0 h
July
- Rain
- 13 days
- Sunshine
- 11.7 h
- Daylight
- 14.7 h
August
- Rain
- 11 days
- Sunshine
- 11.3 h
- Daylight
- 13.7 h
September
- Rain
- 7 days
- Sunshine
- 10.0 h
- Daylight
- 12.4 h
October
- Rain
- 10 days
- Sunshine
- 8.0 h
- Daylight
- 11.1 h
November
- Rain
- 9 days
- Sunshine
- 6.4 h
- Daylight
- 9.9 h
December
- Rain
- 9 days
- Sunshine
- 5.1 h
- Daylight
- 9.4 h
- Snow
- 1 day
Looking for warmer alternatives? Browse warm places by month, or compare Indianapolis's coolest part of the year: January, February, December.
Where Indianapolis sits among other climates
- Indianapolis sits close to the middle of our dataset on most measures: 54°F (12°C) as an annual average, 45.9 inches (1166 mm) of precipitation and 8.5 hours of sun a day.
These comparisons use the same ten-year window for every city in the dataset.