Climate averages 1991–2020
Louisville weather
in September.
A warm, moderately wet month: the 4th warmest and the 2nd driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Louisville: daytime highs average 26.5°C and nights cool to about 16.5°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 77 mm of rain on roughly 8 days, which makes September a moderately wet month (the 2nd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 28 min on an average September day.
The nearest other city in this atlas is Lexington (116 km away). In September its highs average 25.6°C, 0.9°C cooler than Louisville, with 89 mm of rain.
Among the 498 cities listed in the United States, Louisville ranks joint 258th of 498 for the warmest September highs and joint 259th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Louisville is 0.4°C cooler than that mean.
From September to October, average highs fall by 6.6°C to 19.9°C, and monthly rainfall rises from 77 mm to 85 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Louisville climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 5.2°C-2.9°C | -2.9°C | 91 | 9.7 | 9.810 h |
| February | 7.8°C-1.6°C | -1.6°C | 84 | 9.3 | 10.711 h |
| March | 13.0°C2.7°C | 2.7°C | 114 | 11.4 | 11.912 h |
| April | 19.1°C8.3°C | 8.3°C | 127 | 12.0 | 13.213 h |
| May | 23.9°C13.9°C | 13.9°C | 128 | 12.8 | 14.214 h |
| June | 28.5°C18.7°C | 18.7°C | 102 | 11.7 | 14.815 h |
| July | 30.4°C20.8°C | 20.8°C | 101 | 11.8 | 14.515 h |
| August | 30.0°C20.2°C | 20.2°C | 71 | 9.1 | 13.614 h |
| September, selected | 26.5°C16.5°C | 16.5°C | 77 | 7.7 | 12.512 h |
| October | 19.9°C10.2°C | 10.2°C | 85 | 8.1 | 11.211 h |
| November | 12.6°C4.0°C | 4.0°C | 89 | 9.3 | 10.110 h |
| December | 7.1°C-0.5°C | -0.5°C | 102 | 10.1 | 9.610 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Lexington in SeptemberUnited States · 116 kmHigh 25.6°C · Low 15.9°C · 89 mm rain
- Bloomington (Indiana), United States in SeptemberUnited States · 121 kmHigh 25.3°C · Low 15.6°C · 73 mm rain
- Cincinnati in SeptemberUnited States · 145 kmHigh 25.0°C · Low 15.2°C · 68 mm rain
- Evansville in SeptemberUnited States · 160 kmHigh 26.7°C · Low 17.5°C · 82 mm rain
- Indianapolis in SeptemberUnited States · 172 kmHigh 24.6°C · Low 15.2°C · 72 mm rain
- Fishers in SeptemberUnited States · 190 kmHigh 24.4°C · Low 14.8°C · 69 mm rain
- Carmel in SeptemberUnited States · 194 kmHigh 24.2°C · Low 14.8°C · 69 mm rain
- Dayton in SeptemberUnited States · 215 kmHigh 24.4°C · Low 15.3°C · 68 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Louisville) is explained once on the Louisville year overview and on the Sources, method and limits page.