September is one of the warmer months of the year in Keynsham, with average highs near 18.9°C and lows around 10.3°C (mean 14.6°C). It is about average for rainfall, averaging 63 mm of rainfall and 82% relative humidity across the period.
September is one of the warmer months of the year in Keynsham. Across 45 years of records, the warmest September in Keynsham was 2023 — when the month averaged 17.5°C — while the coldest was 1986 at 11.6°C. Typical September days reach 18.9°C with nights near 10.3°C. The long-term trend is warming, about 0.2°C per decade.
September is about average for rainfall in Keynsham, averaging 63 mm of rainfall. The wettest September on record was 2024 with 136 mm, while the driest was 2014 at 16 mm.
Relative humidity in Keynsham during September averages 82%. The most humid September was 2000 at 87%, and the least humid was 1991 at 76%.
September receives about 3.2 kWh/m²/day of solar energy in Keynsham. The sunniest Septembers were 1991 and 2015 at 3.6 kWh/m²/day, and the cloudiest was 2000 at 2.6.
Average wind speed in Keynsham during September is 3.2 m/s. The windiest Septembers were 1983 and 2004 at 4 m/s, while the calmest was 2014 at 2.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.3°C | 14.2°C | 14.9°C | 14.5°C | 15.5°C | +1.2°C |
| Avg High | 18.5°C | 18.5°C | 19.3°C | 18.8°C | 20.0°C | +1.5°C |
| Avg Low | 10.1°C | 9.9°C | 10.6°C | 10.2°C | 11.1°C | +1°C |
| Avg Rain | 64 mm | 75 mm | 49 mm | 59 mm | 72 mm | +8 mm |
September temperatures in Keynsham have risen by about 1.1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 2.9°C (1986) to a record high of 29.2°C (2023).
Rainfall in September is about average for rainfall, averaging 63 mm, with a wettest year of 136 mm.
One of the best times to visit Keynsham
September is one of the best times to visit Keynsham. Expect days averaging 18.9°C and nights around 10.3°C (mean 14.6°C) — warmer than Keynsham's yearly average — with moderate rainfall (63 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 | 19.1°C | 14.7°C | 10.3°C | 22.8°C | 5.1°C | 76 mm | 81% | 3.8 m/s | 3.3 |
| 2024 🌧️ | 18.4°C | 14.5°C | 10.6°C | 23.2°C | 4.6°C | 136 mm | 86% | 3.1 m/s | 2.7 |
| 2023 🔥 | 21.9°C | 17.5°C | 13.2°C | 29.2°C | 7.6°C | 67 mm | 82% | 2.9 m/s | 3.2 |
| 2022 | 19.9°C | 15.4°C | 10.9°C | 26.2°C | 6.1°C | 61 mm | 79% | 3 m/s | 3.1 |
| 2021 | 21.1°C | 16.4°C | 11.7°C | 28.3°C | 8.0°C | 57 mm | 82% | 2.7 m/s | 3.2 |
| 2020 | 19.5°C | 14.6°C | 9.7°C | 26.2°C | 4.4°C | 35 mm | 81% | 3.2 m/s | 3.5 |
| 2019 | 19.2°C | 14.8°C | 10.4°C | 24.6°C | 6.3°C | 108 mm | 82% | 3.5 m/s | 3.4 |
| 2018 | 18.8°C | 14.4°C | 10.0°C | 23.6°C | 3.8°C | 57 mm | 81% | 3.4 m/s | 3.1 |
| 2017 | 17.5°C | 13.7°C | 9.9°C | 21.6°C | 6.6°C | 78 mm | 86% | 3.4 m/s | 2.9 |
| 2016 | 20.0°C | 16.0°C | 11.9°C | 26.1°C | 7.4°C | 68 mm | 85% | 3.3 m/s | 3 |
| 2015 | 17.4°C | 12.8°C | 8.3°C | 20.9°C | 5.0°C | 50 mm | 84% | 2.9 m/s | 3.6 |
| 2014 | 20.6°C | 15.7°C | 10.8°C | 23.0°C | 7.6°C | 16 mm | 81% | 2.2 m/s | 3.4 |
| 2013 | 19.2°C | 14.6°C | 9.9°C | 25.0°C | 7.0°C | 52 mm | 82% | 2.7 m/s | 3 |
| 2012 | 17.1°C | 13.1°C | 9.1°C | 21.6°C | 5.7°C | 72 mm | 85% | 3.3 m/s | 3.4 |
| 2011 | 19.5°C | 15.5°C | 11.5°C | 25.4°C | 8.9°C | 47 mm | 83% | 3.9 m/s | 3.1 |
| 2010 | 18.5°C | 14.2°C | 9.9°C | 22.0°C | 4.0°C | 46 mm | 83% | 3.4 m/s | 3 |
| 2009 | 19.1°C | 14.5°C | 9.9°C | 23.4°C | 7.3°C | 22 mm | 82% | 3.3 m/s | 3.4 |
| 2008 | 17.6°C | 13.7°C | 9.8°C | 19.6°C | 6.7°C | 86 mm | 84% | 3.1 m/s | 3 |
| 2007 | 18.5°C | 14.2°C | 10.0°C | 23.0°C | 4.9°C | 29 mm | 84% | 3.3 m/s | 3.3 |
| 2006 | 21.5°C | 17.1°C | 12.7°C | 26.0°C | 7.9°C | 72 mm | 82% | 3.5 m/s | 3.2 |
| 2005 | 20.5°C | 15.7°C | 10.8°C | 27.5°C | 4.9°C | 38 mm | 81% | 3.1 m/s | 3.3 |
| 2004 | 19.5°C | 15.3°C | 11.1°C | 26.9°C | 7.1°C | 34 mm | 82% | 4 m/s | 3.3 |
| 2003 | 20.2°C | 15.1°C | 10.0°C | 25.4°C | 5.4°C | 17 mm | 77% | 2.5 m/s | 3.4 |
| 2002 | 19.5°C | 14.9°C | 10.3°C | 23.9°C | 6.7°C | 26 mm | 79% | 2.7 m/s | 3.4 |
| 2001 | 17.7°C | 13.8°C | 9.9°C | 21.9°C | 7.3°C | 48 mm | 83% | 3.6 m/s | 2.9 |
| 2000 | 18.8°C | 15.1°C | 11.3°C | 25.8°C | 7.0°C | 118 mm | 87% | 3.2 m/s | 2.6 |
| 1999 | 19.6°C | 15.5°C | 11.4°C | 25.6°C | 7.1°C | 117 mm | 84% | 3.1 m/s | 3.3 |
| 1998 | 19.1°C | 15.2°C | 11.2°C | 23.1°C | 7.1°C | 103 mm | 85% | 3.5 m/s | 3.1 |
| 1997 | 19.3°C | 14.7°C | 10.1°C | 23.5°C | 7.3°C | 25 mm | 83% | 3 m/s | 3.3 |
| 1996 | 18.9°C | 14.2°C | 9.4°C | 23.2°C | 6.2°C | 25 mm | 78% | 3.4 m/s | 3.3 |
| 1995 | 17.7°C | 13.8°C | 9.8°C | 22.0°C | 6.1°C | 113 mm | 82% | 3.2 m/s | 3 |
| 1994 | 16.8°C | 13.0°C | 9.3°C | 20.5°C | 4.2°C | 92 mm | 85% | 3.5 m/s | 3 |
| 1993 | 16.9°C | 12.7°C | 8.5°C | 23.9°C | 3.3°C | 94 mm | 83% | 3.1 m/s | 2.8 |
| 1992 | 17.0°C | 13.4°C | 9.8°C | 20.9°C | 6.1°C | 86 mm | 86% | 3.5 m/s | 3.1 |
| 1991 | 20.9°C | 15.8°C | 10.8°C | 26.8°C | 6.9°C | 53 mm | 76% | 3.1 m/s | 3.6 |
| 1990 | 18.5°C | 13.7°C | 8.9°C | 23.9°C | 4.1°C | 40 mm | 76% | 3.1 m/s | 3.3 |
| 1989 | 20.0°C | 15.6°C | 11.3°C | 25.8°C | 7.5°C | 42 mm | 79% | 3.2 m/s | 2.9 |
| 1988 | 17.8°C | 13.8°C | 9.8°C | 25.3°C | 5.2°C | 59 mm | 82% | 3.7 m/s | 2.9 |
| 1987 | 18.6°C | 14.4°C | 10.1°C | 24.2°C | 4.5°C | 53 mm | 82% | 3.2 m/s | 3 |
| 1986 ❄️ | 16.4°C | 11.6°C | 6.9°C | 19.8°C | 2.9°C | 28 mm | 81% | 2.6 m/s | 3.4 |
| 1985 | 18.9°C | 14.7°C | 10.5°C | 23.3°C | 6.4°C | 31 mm | 85% | 3.1 m/s | 3.2 |
| 1984 | 18.2°C | 14.3°C | 10.4°C | 25.3°C | 6.4°C | 82 mm | 78% | 3.7 m/s | 3.1 |
| 1983 | 18.2°C | 14.3°C | 10.5°C | 23.4°C | 6.4°C | 79 mm | 83% | 4 m/s | — |
| 1982 | 19.8°C | 15.2°C | 10.6°C | 27.4°C | 6.3°C | 71 mm | 83% | 2.9 m/s | — |
| 1981 | 18.7°C | 14.7°C | 10.8°C | 23.2°C | 7.5°C | 129 mm | 82% | 3.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 18.9°C with lows near 10.3°C (mean 14.6°C), based on 45 years of NASA POWER data.
September averages 63 mm of rainfall in Keynsham, about average for rainfall. The wettest on record was 136 mm in 2024.
The hottest September reached 29.2°C in 2023. The coldest dipped to 2.9°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.1°C. Daytime highs moved from 18.8°C to 20.1°C and overnight lows from 10.6°C to 11.3°C over the same span.
September is one of the warmer months of the year in Keynsham and about average for rainfall, so plan for around 18.9°C daytime highs and 10.3°C at night.
Not quite — September is the 10th coolest month in Keynsham, averaging 14.6°C.
For September in Keynsham, pack light layers you can adjust through the day, with typical highs of 18.9°C and lows of 10.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 82% — quite humid.
Average wind speed in September is 3.2 m/s. The windiest September on record averaged 4 m/s (1983).
The wettest September on record was 2024 with 136 mm. On average, September sees 63 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 Keynsham 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.
