September is one of the warmer months of the year in Jacksonville, with average highs near 30.4°C and lows around 21.5°C (mean 26°C). It is a relatively wet time of year, averaging 149 mm of rainfall and 81% relative humidity across the period.
September is one of the warmer months of the year in Jacksonville. Across 45 years of records, the warmest September in Jacksonville was 2019 — when the month averaged 28.1°C — while the coldest was 2001 at 24.1°C. Typical September days reach 30.4°C with nights near 21.5°C. The long-term trend is warming, about 0.3°C per decade.
September is a relatively wet time of year in Jacksonville, averaging 149 mm of rainfall. The wettest September on record was 2004 with 402 mm, while the driest was 2019 at 46 mm.
Relative humidity in Jacksonville during September averages 81%. The most humid September was 2015 at 88%, and the least humid was 1990 at 69%.
September receives about 4.8 kWh/m²/day of solar energy in Jacksonville. The sunniest Septembers were 2018 and 2019 at 5.5 kWh/m²/day, and the cloudiest were 2004, 2015 and 2024, among others at 4.1.
Average wind speed in Jacksonville during September is 0.6 m/s. The windiest September was 2004 at 1 m/s, while the calmest were 2014, 2015 and 2021, 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 | 25.4°C | 26.0°C | 25.8°C | 26.5°C | 26.2°C | +0.8°C |
| Avg High | 29.8°C | 30.6°C | 30.0°C | 31.2°C | 30.6°C | +0.8°C |
| Avg Low | 21.1°C | 21.5°C | 21.5°C | 21.8°C | 21.8°C | +0.7°C |
| Avg Rain | 153 mm | 147 mm | 162 mm | 139 mm | 144 mm | -9 mm |
September temperatures in Jacksonville have risen by about 1.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 10.3°C (1981) to a record high of 37.8°C (2019).
Rainfall in September is a relatively wet time of year, averaging 149 mm, with a wettest year of 402 mm.
A good time to visit Jacksonville
September is a good time to visit Jacksonville, with days averaging 30.4°C and nights around 21.5°C (mean 26°C, warmer than Jacksonville's yearly average) and higher rainfall. October and April are marginally more temperate, but September still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 31.7°C | 26.4°C | 21.0°C | 36.4°C | 16.9°C | 55 mm | 77% | 0.6 m/s | 5.3 |
| 2024 | 30.4°C | 26.6°C | 22.8°C | 35.1°C | 19.3°C | 201 mm | 87% | 0.6 m/s | 4.1 |
| 2023 | 32.1°C | 26.9°C | 21.7°C | 36.7°C | 15.9°C | 137 mm | 76% | 0.6 m/s | 5.1 |
| 2022 | 29.9°C | 25.8°C | 21.7°C | 35.3°C | 15.1°C | 145 mm | 84% | 0.6 m/s | 4.6 |
| 2021 | 30.2°C | 25.8°C | 21.5°C | 33.4°C | 15.6°C | 146 mm | 84% | 0.5 m/s | 5.1 |
| 2020 | 29.6°C | 25.9°C | 22.3°C | 36.2°C | 12.2°C | 180 mm | 86% | 0.6 m/s | 4.5 |
| 2019 🔥 | 33.5°C | 28.1°C | 22.7°C | 37.8°C | 18.1°C | 46 mm | 72% | 0.7 m/s | 5.5 |
| 2018 | 32.3°C | 27.9°C | 23.5°C | 35.3°C | 22.4°C | 78 mm | 80% | 0.6 m/s | 5.5 |
| 2017 | 30.0°C | 25.8°C | 21.6°C | 33.7°C | 18.4°C | 275 mm | 85% | 0.7 m/s | 4.7 |
| 2016 | 31.8°C | 26.8°C | 21.8°C | 35.6°C | 18.7°C | 130 mm | 79% | 0.6 m/s | 5.1 |
| 2015 | 29.1°C | 25.4°C | 21.7°C | 34.8°C | 13.9°C | 176 mm | 88% | 0.5 m/s | 4.1 |
| 2014 | 30.3°C | 26.0°C | 21.7°C | 36.3°C | 15.6°C | 257 mm | 85% | 0.5 m/s | 4.3 |
| 2013 | 30.0°C | 25.8°C | 21.5°C | 33.7°C | 16.9°C | 110 mm | 83% | 0.6 m/s | 4.9 |
| 2012 | 29.7°C | 25.3°C | 20.8°C | 33.2°C | 12.8°C | 108 mm | 84% | 0.6 m/s | 5.2 |
| 2011 | 32.1°C | 26.7°C | 21.2°C | 36.5°C | 16.5°C | 118 mm | 75% | 0.6 m/s | 5.1 |
| 2010 | 32.8°C | 27.3°C | 21.8°C | 37.2°C | 17.7°C | 92 mm | 72% | 0.6 m/s | 5.2 |
| 2009 | 29.3°C | 25.4°C | 21.4°C | 32.3°C | 12.5°C | 91 mm | 85% | 0.6 m/s | 5 |
| 2008 | 29.3°C | 24.9°C | 20.6°C | 33.8°C | 12.6°C | 82 mm | 84% | 0.7 m/s | 5.2 |
| 2007 | 30.7°C | 26.5°C | 22.2°C | 33.9°C | 20.0°C | 137 mm | 81% | 0.7 m/s | 4.9 |
| 2006 | 32.1°C | 26.7°C | 21.3°C | 36.1°C | 14.3°C | 87 mm | 74% | 0.5 m/s | 5.2 |
| 2005 | 31.7°C | 26.8°C | 21.9°C | 36.3°C | 17.3°C | 99 mm | 78% | 0.7 m/s | 5.1 |
| 2004 🌧️ | 28.7°C | 25.6°C | 22.6°C | 32.9°C | 18.3°C | 402 mm | 88% | 1 m/s | 4.1 |
| 2003 | 30.1°C | 25.4°C | 20.7°C | 33.0°C | 16.0°C | 77 mm | 80% | 0.6 m/s | 4.8 |
| 2002 | 31.1°C | 27.1°C | 23.0°C | 33.9°C | 20.6°C | 169 mm | 84% | 0.7 m/s | 5 |
| 2001 ❄️ | 28.2°C | 24.1°C | 20.1°C | 31.9°C | 12.2°C | 233 mm | 85% | 0.6 m/s | 4.4 |
| 2000 | 28.8°C | 25.1°C | 21.3°C | 32.9°C | 15.3°C | 244 mm | 87% | 0.7 m/s | 4.1 |
| 1999 | 30.8°C | 25.8°C | 20.8°C | 36.6°C | 14.8°C | 218 mm | 76% | 0.7 m/s | 4.6 |
| 1998 | 29.7°C | 25.9°C | 22.0°C | 33.7°C | 16.8°C | 213 mm | 85% | 0.7 m/s | 4.4 |
| 1997 | 32.6°C | 27.2°C | 21.8°C | 37.4°C | 18.5°C | 71 mm | 72% | 0.6 m/s | 5.1 |
| 1996 | 30.6°C | 25.7°C | 20.8°C | 33.5°C | 14.5°C | 149 mm | 79% | 0.5 m/s | 5 |
| 1995 | 29.6°C | 25.6°C | 21.7°C | 32.8°C | 16.9°C | 202 mm | 86% | 0.6 m/s | 4.5 |
| 1994 | 29.4°C | 25.1°C | 20.7°C | 35.3°C | 15.1°C | 148 mm | 82% | 0.6 m/s | 4.7 |
| 1993 | 31.0°C | 26.5°C | 22.0°C | 35.0°C | 13.0°C | 134 mm | 78% | 0.6 m/s | 5.1 |
| 1992 | 29.3°C | 25.6°C | 21.9°C | 33.0°C | 16.0°C | 170 mm | 86% | 0.6 m/s | 4.5 |
| 1991 | 29.8°C | 25.5°C | 21.1°C | 34.0°C | 13.7°C | 103 mm | 83% | 0.7 m/s | 4.8 |
| 1990 | 33.0°C | 27.3°C | 21.7°C | 37.7°C | 14.0°C | 63 mm | 69% | 0.6 m/s | 5.2 |
| 1989 | 29.8°C | 25.9°C | 22.1°C | 34.1°C | 18.4°C | 246 mm | 86% | 0.6 m/s | 4.5 |
| 1988 | 29.7°C | 26.0°C | 22.3°C | 33.1°C | 18.1°C | 248 mm | 86% | 0.6 m/s | 4.2 |
| 1987 | 30.5°C | 25.9°C | 21.4°C | 33.3°C | 15.0°C | 129 mm | 79% | 0.5 m/s | 4.4 |
| 1986 | 31.4°C | 26.7°C | 22.0°C | 35.8°C | 20.6°C | 69 mm | 79% | 0.5 m/s | 5.1 |
| 1985 | 28.7°C | 24.7°C | 20.7°C | 33.5°C | 13.2°C | 139 mm | 84% | 0.7 m/s | 4.7 |
| 1984 | 29.6°C | 25.0°C | 20.4°C | 35.9°C | 15.3°C | 212 mm | 78% | 0.8 m/s | 4.4 |
| 1983 | 29.1°C | 24.7°C | 20.2°C | 33.9°C | 12.4°C | 111 mm | 80% | 0.6 m/s | — |
| 1982 | 29.0°C | 24.8°C | 20.6°C | 35.0°C | 11.9°C | 166 mm | 83% | 0.6 m/s | — |
| 1981 | 30.2°C | 25.0°C | 19.9°C | 32.5°C | 10.3°C | 57 mm | 75% | 0.6 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 30.4°C with lows near 21.5°C (mean 26°C), based on 45 years of NASA POWER data.
September averages 149 mm of rainfall in Jacksonville, a relatively wet time of year. The wettest on record was 402 mm in 2004.
The hottest September reached 37.8°C in 2019. The coldest dipped to 10.3°C in 1981.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.5°C. Daytime highs moved from 29.3°C to 30.9°C and overnight lows from 20.4°C to 21.7°C over the same span.
September is one of the warmer months of the year in Jacksonville and a relatively wet time of year, so plan for around 30.4°C daytime highs and 21.5°C at night.
Not quite — September is the 9th coolest month in Jacksonville, averaging 26°C.
For September in Jacksonville, pack light, breathable clothing and sun protection, with typical highs of 30.4°C and lows of 21.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 81% — quite humid.
Average wind speed in September is 0.6 m/s. The windiest September on record averaged 1 m/s (2004).
The wettest September on record was 2004 with 402 mm. On average, September sees 149 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 Jacksonville 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.
