Indianapolis, IN Weather
Indianapolis hourly forecast: next 24 hours
Today's high of 88°F (31°C) is about 9°F (5°C) above the typical September high of 79°F (26°C).
Current conditions in detail
Indianapolis weather tomorrow (Thursday, September 17)
Tomorrow in Indianapolis looks overcast, with a high of 88° and an overnight low of 72°. There is a 67% chance of rain - plan accordingly. Winds top out near 7 mph, and the UV index reaches 6 (high).
Indianapolis 14-day forecast
About the weather in Indianapolis
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.
Indianapolis weather: quick facts
- 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%
Temperatures through 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.
Rain, sun and snow
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.
Season by season
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.
Average temperatures in Indianapolis by month
| Month | High | Low | Rain days | Precipitation | Sunshine | Humidity |
|---|---|---|---|---|---|---|
| January | 38° | 23° | 10 | 3.4 in | 5.1 h/day | 72% |
| February | 43° | 25° | 9 | 3.2 in | 6.6 h/day | 69% |
| March | 52° | 34° | 13 | 5.3 in | 7.4 h/day | 68% |
| April | 62° | 43° | 12 | 4.1 in | 8.7 h/day | 66% |
| May | 73° | 55° | 14 | 4.9 in | 9.9 h/day | 70% |
| June | 82° | 64° | 12 | 4.0 in | 11.6 h/day | 67% |
| July | 85° | 67° | 13 | 4.6 in | 11.7 h/day | 73% |
| August | 83° | 66° | 11 | 3.5 in | 11.3 h/day | 72% |
| September | 79° | 61° | 7 | 2.9 in | 10.0 h/day | 69% |
| October | 66° | 49° | 10 | 3.1 in | 8.0 h/day | 69% |
| November | 52° | 36° | 9 | 3.2 in | 6.4 h/day | 71% |
| December | 44° | 29° | 9 | 3.5 in | 5.1 h/day | 74% |