September is one of the warmer months of the year in Saint Augustine, with average highs near 28.9°C and lows around 24.9°C (mean 26.9°C). It is a relatively wet time of year, averaging 171 mm of rainfall and 80% relative humidity across the period.
September is one of the warmer months of the year in Saint Augustine. Across 45 years of records, the warmest September in Saint Augustine was 2018 — when the month averaged 28.2°C — while the coldest were 1984 and 2001 at 25.6°C. Typical September days reach 28.9°C with nights near 24.9°C. The long-term trend is warming, about 0.2°C per decade.
September is a relatively wet time of year in Saint Augustine, averaging 171 mm of rainfall. The wettest September on record was 2004 with 414 mm, while the driest was 2019 at 46 mm.
Relative humidity in Saint Augustine during September averages 80%. The most humid September was 1988 at 85%, and the least humid was 1990 at 74%.
September receives about 4.8 kWh/m²/day of solar energy in Saint Augustine. The sunniest September was 2018 at 5.6 kWh/m²/day, and the cloudiest was 1998 at 4.1.
Average wind speed in Saint Augustine during September is 2.6 m/s. The windiest September was 2004 at 4 m/s, while the calmest was 2021 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 26.5°C | 26.9°C | 26.7°C | 27.2°C | 27.3°C | +0.8°C |
| Avg High | 28.4°C | 28.9°C | 28.6°C | 29.3°C | 29.3°C | +0.9°C |
| Avg Low | 24.6°C | 24.9°C | 24.8°C | 25.0°C | 25.3°C | +0.7°C |
| Avg Rain | 188 mm | 150 mm | 207 mm | 144 mm | 165 mm | -24 mm |
September temperatures in Saint Augustine have risen by about 1.2°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 18.2°C (1981) to a record high of 33.9°C (2010).
Rainfall in September is a relatively wet time of year, averaging 171 mm, with a wettest year of 414 mm.
A quieter season to visit Saint Augustine
If your dates are flexible, the more temperate months of April and November tend to be the most comfortable for visiting Saint Augustine. That said, September — with days averaging 28.9°C and nights around 24.9°C (mean 26.9°C) and higher rainfall (171 mm) — can still be rewarding for travellers who don't mind the warmth, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 29.2°C | 27.2°C | 25.2°C | 32.1°C | 23.2°C | 94 mm | 78% | 2.7 m/s | 5 |
| 2024 | 29.5°C | 27.6°C | 25.7°C | 32.1°C | 23.5°C | 202 mm | 85% | 2.4 m/s | 4.3 |
| 2023 | 29.9°C | 27.6°C | 25.3°C | 32.8°C | 22.2°C | 129 mm | 77% | 2.4 m/s | 5.2 |
| 2022 | 29.2°C | 27.3°C | 25.3°C | 32.7°C | 18.8°C | 239 mm | 81% | 2.5 m/s | 4.4 |
| 2021 | 28.8°C | 26.8°C | 24.8°C | 31.1°C | 22.7°C | 162 mm | 82% | 2.1 m/s | 4.9 |
| 2020 | 29.0°C | 27.2°C | 25.4°C | 32.9°C | 18.6°C | 162 mm | 83% | 2.8 m/s | 4.4 |
| 2019 | 30.0°C | 27.8°C | 25.6°C | 32.8°C | 23.0°C | 46 mm | 76% | 3.2 m/s | 5.4 |
| 2018 🔥 | 30.1°C | 28.2°C | 26.2°C | 32.4°C | 25.2°C | 89 mm | 82% | 2.3 m/s | 5.6 |
| 2017 | 28.8°C | 26.9°C | 24.9°C | 30.8°C | 22.9°C | 258 mm | 83% | 2.8 m/s | 4.8 |
| 2016 | 29.4°C | 27.2°C | 25.0°C | 31.4°C | 23.6°C | 149 mm | 81% | 2.4 m/s | 4.9 |
| 2015 | 28.6°C | 26.7°C | 24.9°C | 31.8°C | 22.0°C | 192 mm | 85% | 2.3 m/s | 4.3 |
| 2014 | 28.7°C | 26.7°C | 24.7°C | 32.2°C | 22.4°C | 247 mm | 83% | 2.2 m/s | 4.3 |
| 2013 | 28.7°C | 26.7°C | 24.7°C | 32.2°C | 22.5°C | 134 mm | 81% | 2.5 m/s | 4.9 |
| 2012 | 28.6°C | 26.5°C | 24.5°C | 30.9°C | 21.4°C | 104 mm | 81% | 2.4 m/s | 5.1 |
| 2011 | 29.9°C | 27.3°C | 24.6°C | 33.1°C | 22.5°C | 143 mm | 77% | 2.3 m/s | 5.2 |
| 2010 | 30.0°C | 27.6°C | 25.1°C | 33.9°C | 22.6°C | 80 mm | 74% | 2.3 m/s | 5.3 |
| 2009 | 28.2°C | 26.6°C | 25.0°C | 30.3°C | 19.7°C | 138 mm | 82% | 2.6 m/s | 5 |
| 2008 | 28.3°C | 26.3°C | 24.2°C | 31.1°C | 18.9°C | 121 mm | 83% | 2.8 m/s | 5 |
| 2007 | 29.0°C | 27.2°C | 25.4°C | 31.2°C | 24.3°C | 228 mm | 82% | 2.8 m/s | 4.8 |
| 2006 | 29.2°C | 26.9°C | 24.5°C | 32.7°C | 21.7°C | 124 mm | 78% | 2.3 m/s | 5.1 |
| 2005 | 29.4°C | 27.3°C | 25.1°C | 32.6°C | 22.4°C | 109 mm | 79% | 3 m/s | 5 |
| 2004 🌧️ | 28.3°C | 26.8°C | 25.4°C | 30.4°C | 23.3°C | 414 mm | 85% | 4 m/s | 4.3 |
| 2003 | 27.7°C | 25.8°C | 24.0°C | 29.8°C | 21.4°C | 111 mm | 84% | 2.6 m/s | 4.7 |
| 2002 | 29.4°C | 27.5°C | 25.6°C | 31.5°C | 23.0°C | 161 mm | 84% | 2.8 m/s | 4.9 |
| 2001 | 27.5°C | 25.6°C | 23.8°C | 30.9°C | 19.0°C | 345 mm | 82% | 2.7 m/s | 4.3 |
| 2000 | 28.5°C | 26.7°C | 24.8°C | 30.4°C | 22.4°C | 323 mm | 84% | 2.8 m/s | 4.3 |
| 1999 | 28.8°C | 26.6°C | 24.4°C | 33.2°C | 20.9°C | 224 mm | 78% | 2.9 m/s | 4.7 |
| 1998 | 28.4°C | 26.6°C | 24.8°C | 31.4°C | 22.3°C | 193 mm | 84% | 2.7 m/s | 4.1 |
| 1997 | 29.8°C | 27.5°C | 25.1°C | 32.6°C | 22.6°C | 170 mm | 75% | 2.5 m/s | 5.3 |
| 1996 | 29.5°C | 27.1°C | 24.6°C | 32.3°C | 22.9°C | 82 mm | 76% | 2.3 m/s | 5.1 |
| 1995 | 28.4°C | 26.6°C | 24.8°C | 30.3°C | 22.8°C | 145 mm | 84% | 2.5 m/s | 4.8 |
| 1994 | 28.1°C | 26.1°C | 24.0°C | 32.4°C | 20.7°C | 154 mm | 81% | 2.5 m/s | 4.7 |
| 1993 | 29.5°C | 27.4°C | 25.4°C | 32.0°C | 21.7°C | 127 mm | 78% | 2.5 m/s | 5 |
| 1992 | 28.2°C | 26.8°C | 25.3°C | 30.0°C | 22.2°C | 250 mm | 83% | 2.8 m/s | 4.3 |
| 1991 | 28.7°C | 26.9°C | 25.2°C | 31.4°C | 21.1°C | 101 mm | 79% | 2.9 m/s | 5.2 |
| 1990 | 29.6°C | 27.4°C | 25.2°C | 33.4°C | 22.0°C | 56 mm | 74% | 2.6 m/s | 5.2 |
| 1989 | 28.6°C | 26.9°C | 25.1°C | 30.7°C | 23.2°C | 274 mm | 83% | 2.5 m/s | 4.8 |
| 1988 | 28.7°C | 26.9°C | 25.2°C | 30.7°C | 23.2°C | 285 mm | 85% | 2.7 m/s | 4.3 |
| 1987 | 29.2°C | 27.1°C | 24.9°C | 32.0°C | 23.0°C | 179 mm | 77% | 2.2 m/s | 4.5 |
| 1986 | 29.0°C | 26.9°C | 24.9°C | 31.1°C | 24.0°C | 75 mm | 80% | 2.2 m/s | 5.2 |
| 1985 | 28.0°C | 26.3°C | 24.5°C | 31.2°C | 22.5°C | 145 mm | 79% | 3 m/s | 4.8 |
| 1984 ❄️ | 27.7°C | 25.6°C | 23.6°C | 32.1°C | 18.7°C | 232 mm | 80% | 3.3 m/s | 4.6 |
| 1983 | 27.8°C | 26.1°C | 24.4°C | 31.3°C | 20.3°C | 165 mm | 80% | 2.7 m/s | — |
| 1982 | 28.0°C | 26.3°C | 24.6°C | 32.3°C | 20.2°C | 228 mm | 80% | 2.5 m/s | — |
| 1981 | 28.4°C | 26.2°C | 24.1°C | 30.2°C | 18.2°C | 112 mm | 74% | 2.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 28.9°C with lows near 24.9°C (mean 26.9°C), based on 45 years of NASA POWER data.
September averages 171 mm of rainfall in Saint Augustine, a relatively wet time of year. The wettest on record was 414 mm in 2004.
The hottest September reached 33.9°C in 2010. The coldest dipped to 18.2°C in 1981.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.2°C. Daytime highs moved from 28°C to 29.3°C and overnight lows from 24.2°C to 25.3°C over the same span.
September is one of the warmer months of the year in Saint Augustine and a relatively wet time of year, so plan for around 28.9°C daytime highs and 24.9°C at night.
Not quite — September is the 9th coolest month in Saint Augustine, averaging 26.9°C.
For September in Saint Augustine, pack light layers you can adjust through the day, with typical highs of 28.9°C and lows of 24.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 80% — quite humid.
Average wind speed in September is 2.6 m/s. The windiest September on record averaged 4 m/s (2004).
The wettest September on record was 2004 with 414 mm. On average, September sees 171 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 Saint Augustine 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.
