Climate averages 1991–2020
Chattanooga weather
in September.
A warm, wet month: the 4th warmest and the 4th 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 Chattanooga: daytime highs average 27.5°C and nights cool to about 18.1°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 99 mm of rain on roughly 8 days, which makes September a wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 26 min on an average September day.
The nearest other city in this atlas is East Chattanooga (6 km away). In September its highs average 27.4°C, about as warm as Chattanooga, with 99 mm of rain.
Among the 498 cities listed in the United States, Chattanooga ranks joint 223rd of 498 for the warmest September highs and joint 387th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Chattanooga is 0.7°C warmer than that mean.
From September to October, average highs fall by 5.6°C to 22.0°C, and monthly rainfall falls from 99 mm to 84 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
Chattanooga climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 9.6°C0.6°C | 0.6°C | 119 | 10.2 | 10.110 h |
| February | 11.9°C2.1°C | 2.1°C | 113 | 10.2 | 10.911 h |
| March | 16.3°C5.6°C | 5.6°C | 133 | 11.6 | 11.912 h |
| April | 21.2°C10.0°C | 10.0°C | 120 | 10.3 | 13.013 h |
| May | 25.4°C14.9°C | 14.9°C | 101 | 10.6 | 14.014 h |
| June | 29.3°C19.5°C | 19.5°C | 95 | 12.9 | 14.514 h |
| July | 30.9°C21.6°C | 21.6°C | 105 | 13.2 | 14.314 h |
| August | 30.5°C21.2°C | 21.2°C | 85 | 11.3 | 13.513 h |
| September, selected | 27.5°C18.1°C | 18.1°C | 99 | 8.0 | 12.412 h |
| October | 22.0°C12.0°C | 12.0°C | 84 | 7.1 | 11.311 h |
| November | 15.5°C5.9°C | 5.9°C | 106 | 8.7 | 10.410 h |
| December | 10.8°C2.3°C | 2.3°C | 128 | 10.3 | 9.810 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
- East Chattanooga in SeptemberUnited States · 6 kmHigh 27.4°C · Low 18.0°C · 99 mm rain
- Huntsville in SeptemberUnited States · 122 kmHigh 28.1°C · Low 18.6°C · 92 mm rain
- Murfreesboro in SeptemberUnited States · 132 kmHigh 27.7°C · Low 18.0°C · 85 mm rain
- Roswell in SeptemberUnited States · 143 kmHigh 27.1°C · Low 18.2°C · 91 mm rain
- Sandy Springs in SeptemberUnited States · 151 kmHigh 27.2°C · Low 18.2°C · 92 mm rain
- Johns Creek in SeptemberUnited States · 152 kmHigh 27.4°C · Low 18.5°C · 91 mm rain
- Knoxville in SeptemberUnited States · 162 kmHigh 26.7°C · Low 16.8°C · 90 mm rain
- Atlanta in SeptemberUnited States · 167 kmHigh 27.3°C · Low 18.1°C · 89 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 Chattanooga) is explained once on the Chattanooga year overview and on the Sources, method and limits page.
East Chattanooga lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.