| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 2.5° | -5.9° | 82.2mm | 12.1 | 9 |
| February | 5.2° | -4.2° | 64.9mm | 10 | 23 |
| March | 11.4° | 0.8° | 96.6mm | 11.2 | 48 |
| April | 17.9° | 6.3° | 110.5mm | 11.8 | 70 |
| May | 23.2° | 12.3° | 124.4mm | 13.6 | 73 |
| June | 27.9° | 17.3° | 121.6mm | 11.6 | 73 |
| July | 29.6° | 19.2° | 113.8mm | 10.2 | 69 |
| August | 29.2° | 18.7° | 79.3mm | 8.3 | 75 |
| September | 26° | 14.5° | 78.1mm | 7.4 | 85 |
| October | 18.9° | 7.9° | 82.4mm | 9 | 78 |
| November | 11.2° | 1.6° | 74.1mm | 9.5 | 52 |
| December | 5.1° | -3° | 78.9mm | 12.2 | 20 |
January in Indianapolis averages a daily high of 2.5°C with nights around -5.9°C. Expect roughly 12.1 wet days totalling 82.2mm. A hard month to visit for comfort alone.
February in Indianapolis averages a daily high of 5.2°C with nights around -4.2°C. Expect roughly 10 wet days totalling 64.9mm. A hard month to visit for comfort alone.
March in Indianapolis averages a daily high of 11.4°C with nights around 0.8°C. Expect roughly 11.2 wet days totalling 96.6mm. Demanding conditions — pack for it and plan indoor options.
April in Indianapolis averages a daily high of 17.9°C with nights around 6.3°C. Expect roughly 11.8 wet days totalling 110.5mm. Generally workable, with some weather to plan around.
May in Indianapolis averages a daily high of 23.2°C with nights around 12.3°C. Expect roughly 13.6 wet days totalling 124.4mm. Generally workable, with some weather to plan around.
June in Indianapolis averages a daily high of 27.9°C with nights around 17.3°C. Expect roughly 11.6 wet days totalling 121.6mm. Generally workable, with some weather to plan around.
July in Indianapolis averages a daily high of 29.6°C with nights around 19.2°C. Expect roughly 10.2 wet days totalling 113.8mm. Generally workable, with some weather to plan around.
August in Indianapolis averages a daily high of 29.2°C with nights around 18.7°C. Expect roughly 8.3 wet days totalling 79.3mm. Comfortable conditions for being outdoors all day.
September in Indianapolis averages a daily high of 26°C with nights around 14.5°C. Expect roughly 7.4 wet days totalling 78.1mm. Comfortable conditions for being outdoors all day.
October in Indianapolis averages a daily high of 18.9°C with nights around 7.9°C. Expect roughly 9 wet days totalling 82.4mm. Comfortable conditions for being outdoors all day.
November in Indianapolis averages a daily high of 11.2°C with nights around 1.6°C. Expect roughly 9.5 wet days totalling 74.1mm. Demanding conditions — pack for it and plan indoor options.
December in Indianapolis averages a daily high of 5.1°C with nights around -3°C. Expect roughly 12.2 wet days totalling 78.9mm. A hard month to visit for comfort alone.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Indianapolis peaks at 85.
Based on 30 years of records, September–October scores highest for comfort in Indianapolis, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 29.6°C.
May is the wettest, averaging 124.4mm of rain across roughly 13.6 wet days.
January is the coolest month, with average daily highs around 2.5°C.