September is one of the warmer months of the year in Snellville, with average highs near 29.1°C and lows around 16.8°C (mean 23°C). It is about average for rainfall, averaging 98 mm of rainfall and 72% relative humidity across the period.
September is one of the warmer months of the year in Snellville. Across 45 years of records, the warmest September in Snellville was 2019 — when the month averaged 27.3°C — while the coldest was 1994 at 20.3°C. Typical September days reach 29.1°C with nights near 16.8°C. The long-term trend is warming, about 0.5°C per decade.
September is about average for rainfall in Snellville, averaging 98 mm of rainfall. The wettest September on record was 2004 with 308 mm, while the driest was 2005 at 10 mm.
Relative humidity in Snellville during September averages 72%. The most humid September was 1992 at 83%, and the least humid was 1999 at 56%.
September receives about 4.7 kWh/m²/day of solar energy in Snellville. The sunniest September was 2019 at 5.8 kWh/m²/day, and the cloudiest were 1988 and 2002 at 3.8.
Average wind speed in Snellville during September is 0.5 m/s. The windiest September was 2004 at 0.7 m/s, while the calmest were 2022, 2023 and 2025, among others at 0.5 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 22.1°C | 22.6°C | 22.6°C | 24.2°C | 23.2°C | +1.1°C |
| Avg High | 28.3°C | 29.0°C | 28.6°C | 30.5°C | 29.3°C | +1°C |
| Avg Low | 16.0°C | 16.3°C | 16.7°C | 17.9°C | 17.1°C | +1.1°C |
| Avg Rain | 96 mm | 102 mm | 119 mm | 70 mm | 103 mm | +7 mm |
September temperatures in Snellville have risen by about 1.7°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 5.3°C (1983) to a record high of 38.5°C (2019).
Rainfall in September is about average for rainfall, averaging 98 mm, with a wettest year of 308 mm.
One of the best times to visit Snellville
September is one of the best times to visit Snellville. Expect days averaging 29.1°C and nights around 16.8°C (mean 23°C) — warmer than Snellville's yearly average — with higher rainfall (98 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 30.5°C | 23.9°C | 17.4°C | 33.9°C | 12.6°C | 51 mm | 69% | 0.5 m/s | 5.2 |
| 2024 | 29.8°C | 24.2°C | 18.6°C | 36.5°C | 15.3°C | 203 mm | 71% | 0.6 m/s | 4.2 |
| 2023 | 30.2°C | 23.5°C | 16.9°C | 34.7°C | 12.9°C | 48 mm | 68% | 0.5 m/s | 5 |
| 2022 | 29.5°C | 22.9°C | 16.3°C | 35.7°C | 8.5°C | 68 mm | 68% | 0.5 m/s | 5.2 |
| 2021 | 28.3°C | 22.5°C | 16.6°C | 32.6°C | 8.9°C | 88 mm | 73% | 0.5 m/s | 4.8 |
| 2020 | 27.3°C | 22.1°C | 16.9°C | 33.5°C | 8.9°C | 163 mm | 78% | 0.6 m/s | 4.5 |
| 2019 🔥 | 34.9°C | 27.3°C | 19.8°C | 38.5°C | 14.4°C | 17 mm | 58% | 0.5 m/s | 5.8 |
| 2018 | 32.5°C | 26.6°C | 20.6°C | 35.4°C | 18.7°C | 56 mm | 72% | 0.5 m/s | 4.8 |
| 2017 | 28.5°C | 22.2°C | 15.9°C | 33.8°C | 10.6°C | 109 mm | 70% | 0.6 m/s | 5.3 |
| 2016 | 32.5°C | 25.7°C | 18.9°C | 36.1°C | 10.7°C | 40 mm | 66% | 0.5 m/s | 5.4 |
| 2015 | 28.2°C | 22.7°C | 17.2°C | 34.4°C | 9.9°C | 96 mm | 76% | 0.5 m/s | 4.4 |
| 2014 | 30.1°C | 24.3°C | 18.4°C | 34.5°C | 12.1°C | 74 mm | 74% | 0.5 m/s | 4.4 |
| 2013 | 27.3°C | 21.9°C | 16.5°C | 31.3°C | 10.4°C | 61 mm | 80% | 0.5 m/s | 4.9 |
| 2012 | 29.1°C | 22.8°C | 16.6°C | 34.7°C | 8.3°C | 79 mm | 72% | 0.5 m/s | 4.6 |
| 2011 | 29.3°C | 23.1°C | 16.9°C | 37.0°C | 12.2°C | 74 mm | 68% | 0.5 m/s | 4.5 |
| 2010 | 32.1°C | 24.9°C | 17.7°C | 36.3°C | 13.4°C | 98 mm | 62% | 0.5 m/s | 5.6 |
| 2009 | 27.6°C | 22.6°C | 17.7°C | 34.7°C | 8.0°C | 277 mm | 79% | 0.5 m/s | 3.9 |
| 2008 | 29.5°C | 23.3°C | 17.1°C | 34.9°C | 10.7°C | 23 mm | 70% | 0.5 m/s | 4.9 |
| 2007 | 31.5°C | 24.7°C | 17.9°C | 35.3°C | 10.5°C | 40 mm | 63% | 0.5 m/s | 5 |
| 2006 | 28.5°C | 22.1°C | 15.7°C | 33.3°C | 8.5°C | 88 mm | 72% | 0.5 m/s | 4.8 |
| 2005 | 29.9°C | 23.4°C | 16.9°C | 33.7°C | 13.8°C | 10 mm | 71% | 0.6 m/s | 5.5 |
| 2004 🌧️ | 26.3°C | 21.5°C | 16.7°C | 31.2°C | 10.6°C | 308 mm | 82% | 0.7 m/s | 4.4 |
| 2003 | 27.0°C | 21.3°C | 15.7°C | 31.2°C | 6.5°C | 73 mm | 76% | 0.5 m/s | 5 |
| 2002 | 29.9°C | 24.3°C | 18.7°C | 36.9°C | 14.8°C | 176 mm | 74% | 0.6 m/s | 3.8 |
| 2001 | 28.4°C | 21.6°C | 14.7°C | 33.2°C | 6.0°C | 64 mm | 66% | 0.5 m/s | 5 |
| 2000 | 27.0°C | 21.3°C | 15.6°C | 31.6°C | 6.9°C | 135 mm | 78% | 0.6 m/s | 4.2 |
| 1999 | 30.7°C | 22.8°C | 14.9°C | 36.9°C | 7.0°C | 74 mm | 56% | 0.5 m/s | 5 |
| 1998 | 31.6°C | 24.7°C | 17.9°C | 35.2°C | 11.3°C | 74 mm | 67% | 0.5 m/s | 4.7 |
| 1997 | 30.2°C | 23.6°C | 17.1°C | 35.4°C | 11.4°C | 169 mm | 65% | 0.5 m/s | 4.8 |
| 1996 | 28.1°C | 21.9°C | 15.7°C | 33.6°C | 10.8°C | 125 mm | 73% | 0.5 m/s | 4.4 |
| 1995 | 27.5°C | 21.8°C | 16.0°C | 33.6°C | 9.0°C | 79 mm | 78% | 0.5 m/s | 4.6 |
| 1994 ❄️ | 25.7°C | 20.3°C | 15.0°C | 30.1°C | 8.9°C | 125 mm | 81% | 0.5 m/s | 4.8 |
| 1993 | 31.2°C | 24.0°C | 16.9°C | 35.8°C | 6.3°C | 65 mm | 64% | 0.5 m/s | 4.9 |
| 1992 | 26.8°C | 21.9°C | 16.9°C | 32.1°C | 8.1°C | 158 mm | 83% | 0.5 m/s | 4 |
| 1991 | 27.7°C | 21.9°C | 16.1°C | 34.4°C | 6.8°C | 57 mm | 77% | 0.5 m/s | 4.9 |
| 1990 | 30.0°C | 23.4°C | 16.7°C | 37.0°C | 6.3°C | 99 mm | 68% | 0.5 m/s | 5.1 |
| 1989 | 26.6°C | 21.6°C | 16.6°C | 32.0°C | 9.4°C | 234 mm | 80% | 0.6 m/s | 3.9 |
| 1988 | 27.2°C | 22.0°C | 16.8°C | 32.3°C | 11.8°C | 165 mm | 81% | 0.5 m/s | 3.8 |
| 1987 | 29.6°C | 23.2°C | 16.8°C | 33.4°C | 10.7°C | 69 mm | 68% | 0.5 m/s | 4.5 |
| 1986 | 29.6°C | 23.7°C | 17.9°C | 34.5°C | 14.2°C | 83 mm | 75% | 0.5 m/s | 4.1 |
| 1985 | 28.8°C | 22.0°C | 15.2°C | 33.7°C | 7.3°C | 42 mm | 68% | 0.5 m/s | 5 |
| 1984 | 27.8°C | 21.1°C | 14.4°C | 33.3°C | 8.9°C | 13 mm | 68% | 0.6 m/s | 5.1 |
| 1983 | 26.9°C | 21.2°C | 15.6°C | 34.2°C | 5.3°C | 144 mm | 75% | 0.5 m/s | — |
| 1982 | 27.9°C | 21.7°C | 15.5°C | 33.1°C | 6.9°C | 61 mm | 70% | 0.5 m/s | — |
| 1981 | 30.1°C | 22.7°C | 15.4°C | 33.0°C | 8.0°C | 58 mm | 61% | 0.5 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 29.1°C with lows near 16.8°C (mean 23°C), based on 45 years of NASA POWER data.
September averages 98 mm of rainfall in Snellville, about average for rainfall. The wettest on record was 308 mm in 2004.
The hottest September reached 38.5°C in 2019. The coldest dipped to 5.3°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.7°C. Daytime highs moved from 28.3°C to 29.7°C and overnight lows from 15.2°C to 17.2°C over the same span.
September is one of the warmer months of the year in Snellville and about average for rainfall, so plan for around 29.1°C daytime highs and 16.8°C at night.
Not quite — September is the 9th coolest month in Snellville, averaging 23°C.
For September in Snellville, pack light layers you can adjust through the day, with typical highs of 29.1°C and lows of 16.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 72% — moderately humid.
Average wind speed in September is 0.5 m/s. The windiest September on record averaged 0.7 m/s (2004).
The wettest September on record was 2004 with 308 mm. On average, September sees 98 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Snellville behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.
