September is one of the warmer months of the year in Bay Shore, with average highs near 21.7°C and lows around 18.3°C (mean 20°C). It is about average for rainfall, averaging 98 mm of rainfall and 78% relative humidity across the period.
September is one of the warmer months of the year in Bay Shore. Across 45 years of records, the warmest September in Bay Shore was 2015 — when the month averaged 21.9°C — while the coldest was 1984 at 18.3°C. Typical September days reach 21.7°C with nights near 18.3°C. The long-term trend is warming, about 0.5°C per decade.
September is about average for rainfall in Bay Shore, averaging 98 mm of rainfall. The wettest September on record was 2023 with 309 mm, while the driest was 2024 at 14 mm.
Relative humidity in Bay Shore during September averages 78%. The most humid September was 2011 at 88%, and the least humid was 1983 at 71%.
September receives about 4.4 kWh/m²/day of solar energy in Bay Shore. The sunniest Septembers were 1984, 2005 and 2007 at 5 kWh/m²/day, and the cloudiest was 2018 at 3.7.
Average wind speed in Bay Shore during September is 4.6 m/s. The windiest September was 2010 at 5.3 m/s, while the calmest were 2005 and 2011 at 4.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 19.3°C | 19.5°C | 20.1°C | 20.7°C | 20.8°C | +1.5°C |
| Avg High | 21.2°C | 21.2°C | 21.7°C | 22.3°C | 22.4°C | +1.2°C |
| Avg Low | 17.4°C | 17.8°C | 18.5°C | 19.0°C | 19.2°C | +1.8°C |
| Avg Rain | 83 mm | 102 mm | 105 mm | 92 mm | 113 mm | +30 mm |
September temperatures in Bay Shore have risen by about 1.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 9.9°C (1992) to a record high of 28.8°C (1983).
Rainfall in September is about average for rainfall, averaging 98 mm, with a wettest year of 309 mm.
One of the best times to visit Bay Shore
September is one of the best times to visit Bay Shore. Expect days averaging 21.7°C and nights around 18.3°C (mean 20°C) — warmer than Bay Shore'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 | 22.4°C | 20.9°C | 19.4°C | 25.0°C | 17.3°C | 55 mm | 79% | 4.3 m/s | 4.5 |
| 2024 | 21.7°C | 20.1°C | 18.5°C | 24.4°C | 16.3°C | 14 mm | 79% | 4.6 m/s | 4.3 |
| 2023 🌧️ | 22.5°C | 20.9°C | 19.3°C | 28.7°C | 14.7°C | 309 mm | 81% | 4.8 m/s | 4 |
| 2022 | 22.7°C | 21.0°C | 19.3°C | 27.0°C | 12.8°C | 142 mm | 76% | 4.8 m/s | 4.6 |
| 2021 | 22.9°C | 21.3°C | 19.7°C | 25.6°C | 15.4°C | 104 mm | 82% | 4.9 m/s | 4.6 |
| 2020 | 22.1°C | 20.4°C | 18.8°C | 26.6°C | 13.4°C | 54 mm | 78% | 4.7 m/s | 4.4 |
| 2019 | 22.2°C | 20.5°C | 18.8°C | 23.8°C | 14.1°C | 41 mm | 79% | 4.5 m/s | 4.7 |
| 2018 | 22.7°C | 21.4°C | 20.0°C | 28.5°C | 16.8°C | 196 mm | 86% | 4.5 m/s | 3.7 |
| 2017 | 21.9°C | 20.1°C | 18.3°C | 25.7°C | 14.3°C | 62 mm | 82% | 4.6 m/s | 4.4 |
| 2016 | 22.7°C | 21.2°C | 19.7°C | 26.6°C | 15.8°C | 95 mm | 78% | 5 m/s | 4.1 |
| 2015 🔥 | 23.6°C | 21.9°C | 20.1°C | 27.1°C | 16.1°C | 81 mm | 79% | 4.4 m/s | 4.8 |
| 2014 | 22.2°C | 20.5°C | 18.8°C | 26.7°C | 14.1°C | 51 mm | 76% | 4.3 m/s | 4.5 |
| 2013 | 21.1°C | 19.1°C | 17.1°C | 25.2°C | 12.1°C | 50 mm | 74% | 4.4 m/s | 4.9 |
| 2012 | 22.3°C | 20.8°C | 19.3°C | 26.9°C | 15.5°C | 102 mm | 75% | 4.6 m/s | 4.5 |
| 2011 | 21.4°C | 20.1°C | 18.8°C | 24.1°C | 13.1°C | 144 mm | 88% | 4.2 m/s | 3.9 |
| 2010 | 22.7°C | 21.0°C | 19.2°C | 27.5°C | 15.8°C | 95 mm | 77% | 5.3 m/s | 4.5 |
| 2009 | 21.0°C | 19.4°C | 17.7°C | 25.0°C | 12.6°C | 72 mm | 77% | 4.7 m/s | 4.3 |
| 2008 | 21.4°C | 20.0°C | 18.6°C | 25.6°C | 15.3°C | 186 mm | 81% | 4.4 m/s | 4.3 |
| 2007 | 22.1°C | 20.5°C | 18.9°C | 25.3°C | 14.5°C | 32 mm | 77% | 4.3 m/s | 5 |
| 2006 | 20.9°C | 19.4°C | 17.8°C | 23.5°C | 13.7°C | 91 mm | 80% | 4.8 m/s | 4.1 |
| 2005 | 23.6°C | 21.8°C | 20.0°C | 26.5°C | 13.2°C | 38 mm | 74% | 4.2 m/s | 5 |
| 2004 | 22.3°C | 20.6°C | 18.9°C | 24.9°C | 13.7°C | 179 mm | 81% | 4.3 m/s | 4.4 |
| 2003 | 21.5°C | 20.1°C | 18.7°C | 23.2°C | 13.8°C | 114 mm | 83% | 4.8 m/s | 4.1 |
| 2002 | 22.0°C | 20.4°C | 18.8°C | 25.3°C | 15.1°C | 131 mm | 81% | 4.5 m/s | 4.6 |
| 2001 | 21.5°C | 19.9°C | 18.2°C | 25.1°C | 13.0°C | 81 mm | 75% | 4.6 m/s | 4.7 |
| 2000 | 20.7°C | 18.9°C | 17.2°C | 25.0°C | 10.6°C | 126 mm | 79% | 4.7 m/s | 4.4 |
| 1999 | 21.9°C | 20.3°C | 18.8°C | 24.3°C | 12.5°C | 163 mm | 81% | 5 m/s | 4.2 |
| 1998 | 22.1°C | 20.4°C | 18.6°C | 25.6°C | 14.1°C | 63 mm | 77% | 4.5 m/s | 4.7 |
| 1997 | 21.1°C | 19.2°C | 17.3°C | 23.9°C | 12.8°C | 38 mm | 78% | 5 m/s | 4.4 |
| 1996 | 21.0°C | 19.3°C | 17.7°C | 26.4°C | 13.4°C | 144 mm | 83% | 4.8 m/s | 3.9 |
| 1995 | 21.3°C | 19.7°C | 18.0°C | 26.1°C | 14.1°C | 97 mm | 73% | 4.9 m/s | 4.4 |
| 1994 | 20.7°C | 18.8°C | 16.9°C | 24.1°C | 13.2°C | 89 mm | 77% | 5.1 m/s | 4.5 |
| 1993 | 21.3°C | 19.7°C | 18.1°C | 26.3°C | 12.0°C | 143 mm | 78% | 4.8 m/s | 3.8 |
| 1992 | 20.5°C | 18.9°C | 17.4°C | 23.3°C | 9.9°C | 94 mm | 80% | 5.1 m/s | 3.9 |
| 1991 | 21.1°C | 19.3°C | 17.5°C | 25.7°C | 10.7°C | 116 mm | 75% | 4.8 m/s | 4.3 |
| 1990 | 20.9°C | 19.2°C | 17.5°C | 24.4°C | 11.9°C | 74 mm | 78% | 4.4 m/s | 4.3 |
| 1989 | 21.2°C | 19.4°C | 17.7°C | 26.3°C | 10.7°C | 135 mm | 80% | 4.9 m/s | 4.3 |
| 1988 | 20.5°C | 18.5°C | 16.5°C | 23.3°C | 12.6°C | 80 mm | 74% | 4.3 m/s | 4.6 |
| 1987 | 21.0°C | 19.4°C | 17.8°C | 24.5°C | 14.2°C | 119 mm | 81% | 4.5 m/s | 4.3 |
| 1986 | 20.6°C | 18.8°C | 17.1°C | 23.7°C | 11.8°C | 43 mm | 76% | 4.6 m/s | 4.3 |
| 1985 | 22.1°C | 20.2°C | 18.3°C | 27.4°C | 13.6°C | 72 mm | 74% | 4.4 m/s | 4.7 |
| 1984 ❄️ | 20.3°C | 18.3°C | 16.3°C | 23.5°C | 11.2°C | 75 mm | 74% | 4.4 m/s | 5 |
| 1983 | 23.0°C | 20.9°C | 18.8°C | 28.8°C | 13.5°C | 74 mm | 71% | 4.6 m/s | — |
| 1982 | 21.1°C | 19.2°C | 17.2°C | 25.6°C | 14.8°C | 45 mm | 77% | 4.3 m/s | — |
| 1981 | 20.9°C | 18.8°C | 16.6°C | 25.1°C | 10.7°C | 103 mm | 76% | 5.2 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 21.7°C with lows near 18.3°C (mean 20°C), based on 45 years of NASA POWER data.
September averages 98 mm of rainfall in Bay Shore, about average for rainfall. The wettest on record was 309 mm in 2023.
The hottest September reached 28.8°C in 1983. The coldest dipped to 9.9°C in 1992.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.3°C. Daytime highs moved from 21.5°C to 22.4°C and overnight lows from 17.4°C to 19.2°C over the same span.
September is one of the warmer months of the year in Bay Shore and about average for rainfall, so plan for around 21.7°C daytime highs and 18.3°C at night.
Not quite — September is the 10th coolest month in Bay Shore, averaging 20°C.
For September in Bay Shore, pack light layers you can adjust through the day, with typical highs of 21.7°C and lows of 18.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 78% — quite humid.
Average wind speed in September is 4.6 m/s. The windiest September on record averaged 5.3 m/s (2010).
The wettest September on record was 2023 with 309 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 Bay Shore 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.
