September is one of the warmer months of the year in Syracuse, with average highs near 23°C and lows around 11.6°C (mean 17.3°C). It is about average for rainfall, averaging 98 mm of rainfall and 73% relative humidity across the period.
September is one of the warmer months of the year in Syracuse. Across 45 years of records, the warmest September in Syracuse was 2015 — when the month averaged 20.4°C — while the coldest were 1981 and 1984 at 15.2°C. Typical September days reach 23°C with nights near 11.6°C. The long-term trend is warming, about 0.6°C per decade.
September is about average for rainfall in Syracuse, averaging 98 mm of rainfall. The wettest September on record was 2011 with 181 mm, while the driest was 2017 at 50 mm.
Relative humidity in Syracuse during September averages 73%. The most humid September was 2011 at 82%, and the least humid was 1983 at 64%.
September receives about 4 kWh/m²/day of solar energy in Syracuse. The sunniest September was 2016 at 4.7 kWh/m²/day, and the cloudiest were 1990, 1993 and 2006 at 3.3.
Average wind speed in Syracuse during September is 0.4 m/s. The windiest September was 1983 at 0.5 m/s, while the calmest were 2023, 2024 and 2025, among others at 0.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 16.5°C | 16.4°C | 17.7°C | 18.2°C | 18.0°C | +1.5°C |
| Avg High | 22.2°C | 22.1°C | 23.4°C | 23.9°C | 23.6°C | +1.4°C |
| Avg Low | 10.9°C | 10.8°C | 11.9°C | 12.5°C | 12.4°C | +1.5°C |
| Avg Rain | 108 mm | 101 mm | 97 mm | 101 mm | 79 mm | -29 mm |
September temperatures in Syracuse have risen by about 1.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -1.5°C (1991) to a record high of 34.4°C (1999).
Rainfall in September is about average for rainfall, averaging 98 mm, with a wettest year of 181 mm.
One of the best times to visit Syracuse
September is one of the best times to visit Syracuse. Expect days averaging 23°C and nights around 11.6°C (mean 17.3°C) — warmer than Syracuse'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 | 24.8°C | 18.5°C | 12.1°C | 27.9°C | 6.6°C | 51 mm | 69% | 0.4 m/s | 4.6 |
| 2024 | 24.4°C | 18.9°C | 13.4°C | 29.7°C | 8.2°C | 77 mm | 75% | 0.4 m/s | 4.4 |
| 2023 | 24.0°C | 18.3°C | 12.5°C | 34.3°C | 6.6°C | 53 mm | 75% | 0.4 m/s | 4.4 |
| 2022 | 21.8°C | 17.1°C | 12.3°C | 29.4°C | 2.5°C | 144 mm | 79% | 0.4 m/s | 3.5 |
| 2021 | 22.7°C | 17.6°C | 12.5°C | 28.0°C | 7.1°C | 96 mm | 80% | 0.4 m/s | 3.9 |
| 2020 | 23.6°C | 17.7°C | 11.8°C | 32.8°C | 2.1°C | 52 mm | 69% | 0.4 m/s | 4.1 |
| 2019 | 23.9°C | 17.9°C | 12.0°C | 30.8°C | 8.1°C | 75 mm | 75% | 0.4 m/s | 4.3 |
| 2018 | 24.6°C | 19.5°C | 14.4°C | 33.6°C | 6.8°C | 109 mm | 76% | 0.4 m/s | 4.1 |
| 2017 | 24.9°C | 18.9°C | 12.8°C | 33.5°C | 5.8°C | 50 mm | 73% | 0.4 m/s | 4.5 |
| 2016 | 25.8°C | 19.4°C | 13.0°C | 33.5°C | 5.3°C | 66 mm | 68% | 0.4 m/s | 4.7 |
| 2015 🔥 | 26.5°C | 20.4°C | 14.3°C | 33.9°C | 7.4°C | 115 mm | 69% | 0.4 m/s | 4.2 |
| 2014 | 23.2°C | 17.0°C | 10.9°C | 31.2°C | 1.9°C | 60 mm | 73% | 0.4 m/s | 4.3 |
| 2013 | 21.2°C | 15.4°C | 9.7°C | 30.8°C | 3.0°C | 105 mm | 76% | 0.4 m/s | 4.3 |
| 2012 | 22.9°C | 17.4°C | 11.8°C | 30.6°C | 5.9°C | 101 mm | 70% | 0.4 m/s | 4 |
| 2011 🌧️ | 22.7°C | 18.1°C | 13.4°C | 31.9°C | 5.3°C | 181 mm | 82% | 0.4 m/s | 3.8 |
| 2010 | 22.8°C | 17.5°C | 12.2°C | 33.4°C | 5.5°C | 145 mm | 72% | 0.4 m/s | 3.5 |
| 2009 | 22.1°C | 16.6°C | 11.1°C | 26.8°C | 4.2°C | 75 mm | 75% | 0.4 m/s | 4.3 |
| 2008 | 23.8°C | 17.9°C | 12.1°C | 31.6°C | 4.7°C | 64 mm | 75% | 0.4 m/s | 3.9 |
| 2007 | 24.9°C | 18.6°C | 12.3°C | 34.0°C | 4.9°C | 96 mm | 70% | 0.4 m/s | 4.4 |
| 2006 | 20.4°C | 15.6°C | 10.8°C | 26.3°C | 4.1°C | 122 mm | 81% | 0.4 m/s | 3.3 |
| 2005 | 25.2°C | 19.0°C | 12.8°C | 31.6°C | 6.1°C | 82 mm | 70% | 0.4 m/s | 4.5 |
| 2004 | 23.2°C | 18.0°C | 12.9°C | 28.0°C | 5.7°C | 111 mm | 80% | 0.4 m/s | 4.4 |
| 2003 | 23.0°C | 17.7°C | 12.4°C | 29.6°C | 6.4°C | 108 mm | 75% | 0.4 m/s | 4.1 |
| 2002 | 25.9°C | 19.6°C | 13.4°C | 34.3°C | 5.8°C | 116 mm | 66% | 0.4 m/s | 4.5 |
| 2001 | 22.8°C | 17.0°C | 11.1°C | 32.6°C | 3.3°C | 106 mm | 67% | 0.4 m/s | 4.3 |
| 2000 | 22.6°C | 16.5°C | 10.3°C | 32.7°C | -1.1°C | 87 mm | 69% | 0.4 m/s | 4.1 |
| 1999 | 24.6°C | 18.7°C | 12.8°C | 34.4°C | 5.6°C | 156 mm | 71% | 0.4 m/s | 4 |
| 1998 | 23.7°C | 17.9°C | 12.1°C | 31.1°C | 5.8°C | 65 mm | 72% | 0.4 m/s | 4.1 |
| 1997 | 21.4°C | 15.8°C | 10.2°C | 28.3°C | 3.1°C | 95 mm | 72% | 0.4 m/s | 3.7 |
| 1996 | 22.2°C | 17.2°C | 12.2°C | 30.8°C | 4.7°C | 130 mm | 78% | 0.4 m/s | 3.5 |
| 1995 | 21.9°C | 15.4°C | 9.0°C | 28.8°C | 1.6°C | 68 mm | 67% | 0.4 m/s | 3.9 |
| 1994 | 20.9°C | 15.8°C | 10.7°C | 28.9°C | 6.2°C | 73 mm | 76% | 0.4 m/s | 3.9 |
| 1993 | 21.2°C | 15.7°C | 10.3°C | 30.4°C | 2.3°C | 105 mm | 74% | 0.4 m/s | 3.3 |
| 1992 | 21.4°C | 15.7°C | 10.1°C | 28.6°C | 0.3°C | 119 mm | 77% | 0.4 m/s | 3.9 |
| 1991 | 21.9°C | 15.8°C | 9.6°C | 32.0°C | -1.5°C | 103 mm | 67% | 0.4 m/s | 3.9 |
| 1990 | 21.9°C | 16.3°C | 10.8°C | 30.3°C | 3.9°C | 93 mm | 72% | 0.4 m/s | 3.3 |
| 1989 | 22.9°C | 17.2°C | 11.5°C | 32.0°C | 1.2°C | 133 mm | 72% | 0.4 m/s | 3.8 |
| 1988 | 22.0°C | 16.1°C | 10.1°C | 28.9°C | 2.4°C | 57 mm | 68% | 0.4 m/s | 4.3 |
| 1987 | 21.2°C | 16.3°C | 11.4°C | 27.5°C | 5.0°C | 142 mm | 78% | 0.4 m/s | 3.5 |
| 1986 | 21.5°C | 16.1°C | 10.7°C | 26.5°C | 4.8°C | 119 mm | 76% | 0.4 m/s | 3.5 |
| 1985 | 23.8°C | 17.7°C | 11.6°C | 30.5°C | 4.2°C | 117 mm | 72% | 0.4 m/s | 4.2 |
| 1984 | 20.9°C | 15.2°C | 9.6°C | 27.5°C | 3.0°C | 82 mm | 73% | 0.4 m/s | 4.1 |
| 1983 | 24.5°C | 18.0°C | 11.6°C | 32.3°C | 4.9°C | 66 mm | 64% | 0.5 m/s | — |
| 1982 | 23.4°C | 17.0°C | 10.6°C | 31.4°C | 5.5°C | 86 mm | 70% | 0.4 m/s | — |
| 1981 ❄️ | 19.7°C | 15.2°C | 10.7°C | 28.1°C | 0.7°C | 166 mm | 80% | 0.4 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 23°C with lows near 11.6°C (mean 17.3°C), based on 45 years of NASA POWER data.
September averages 98 mm of rainfall in Syracuse, about average for rainfall. The wettest on record was 181 mm in 2011.
The hottest September reached 34.4°C in 1999. The coldest dipped to -1.5°C in 1991.
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 22.5°C to 23.5°C and overnight lows from 10.8°C to 12.6°C over the same span.
September is one of the warmer months of the year in Syracuse and about average for rainfall, so plan for around 23°C daytime highs and 11.6°C at night.
Not quite — September is the 9th coolest month in Syracuse, averaging 17.3°C.
For September in Syracuse, pack light layers you can adjust through the day, with typical highs of 23°C and lows of 11.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 73% — moderately humid.
Average wind speed in September is 0.4 m/s. The windiest September on record averaged 0.5 m/s (1983).
The wettest September on record was 2011 with 181 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 Syracuse 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.
