September is one of the warmer months of the year in Brighton, with average highs near 18.8°C and lows around 11.6°C (mean 15.2°C). It is about average for rainfall, averaging 60 mm of rainfall and 83% relative humidity across the period.
September is one of the warmer months of the year in Brighton. Across 45 years of records, the warmest September in Brighton was 2023 — when the month averaged 18.4°C — while the coldest was 1986 at 12.5°C. Typical September days reach 18.8°C with nights near 11.6°C. The long-term trend is warming, about 0.3°C per decade.
September is about average for rainfall in Brighton, averaging 60 mm of rainfall. The wettest September on record was 1995 with 122 mm, while the driest was 1997 at 12 mm.
Relative humidity in Brighton during September averages 83%. The most humid September was 2000 at 87%, and the least humid was 1990 at 75%.
September receives about 3.5 kWh/m²/day of solar energy in Brighton. The sunniest Septembers were 1997, 2003 and 2015 at 3.9 kWh/m²/day, and the cloudiest was 2000 at 2.9.
Average wind speed in Brighton during September is 3.8 m/s. The windiest September was 2025 at 4.7 m/s, while the calmest were 2003 and 2014 at 2.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.8°C | 14.8°C | 15.4°C | 15.1°C | 16.4°C | +1.6°C |
| Avg High | 18.3°C | 18.3°C | 19.0°C | 18.7°C | 20.0°C | +1.7°C |
| Avg Low | 11.2°C | 11.3°C | 11.9°C | 11.4°C | 12.7°C | +1.5°C |
| Avg Rain | 58 mm | 75 mm | 51 mm | 50 mm | 66 mm | +9 mm |
September temperatures in Brighton have risen by about 1.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 4.8°C (1988) to a record high of 28.9°C (2023).
Rainfall in September is about average for rainfall, averaging 60 mm, with a wettest year of 122 mm.
One of the best times to visit Brighton
September is one of the best times to visit Brighton. Expect days averaging 18.8°C and nights around 11.6°C (mean 15.2°C) — warmer than Brighton's yearly average — with moderate rainfall (60 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 | 19.3°C | 15.7°C | 12.1°C | 23.5°C | 6.9°C | 52 mm | 79% | 4.7 m/s | 3.5 |
| 2024 | 19.1°C | 15.7°C | 12.3°C | 25.3°C | 5.7°C | 118 mm | 84% | 3.9 m/s | 3.1 |
| 2023 🔥 | 22.0°C | 18.4°C | 14.7°C | 28.9°C | 9.6°C | 47 mm | 83% | 3.3 m/s | 3.6 |
| 2022 | 19.5°C | 16.0°C | 12.4°C | 23.9°C | 7.3°C | 89 mm | 80% | 3.4 m/s | 3.4 |
| 2021 | 20.5°C | 16.8°C | 13.1°C | 25.5°C | 7.7°C | 46 mm | 85% | 3.3 m/s | 3.7 |
| 2020 | 19.8°C | 15.8°C | 11.8°C | 24.9°C | 6.6°C | 47 mm | 79% | 4 m/s | 3.6 |
| 2019 | 19.4°C | 15.5°C | 11.6°C | 23.4°C | 8.1°C | 77 mm | 80% | 4.3 m/s | 3.6 |
| 2018 | 19.0°C | 15.1°C | 11.2°C | 22.3°C | 6.0°C | 41 mm | 78% | 3.8 m/s | 3.7 |
| 2017 | 18.0°C | 14.6°C | 11.1°C | 21.3°C | 7.0°C | 63 mm | 83% | 3.8 m/s | 3.2 |
| 2016 | 20.2°C | 16.7°C | 13.2°C | 24.8°C | 9.3°C | 41 mm | 84% | 3.6 m/s | 3.4 |
| 2015 | 17.1°C | 13.6°C | 10.0°C | 19.5°C | 7.1°C | 61 mm | 83% | 3.7 m/s | 3.9 |
| 2014 | 20.1°C | 16.3°C | 12.5°C | 23.0°C | 7.5°C | 15 mm | 85% | 2.7 m/s | 3.6 |
| 2013 | 18.4°C | 14.8°C | 11.1°C | 26.3°C | 7.1°C | 54 mm | 85% | 3.3 m/s | 3.3 |
| 2012 | 17.9°C | 14.1°C | 10.2°C | 23.4°C | 6.3°C | 57 mm | 82% | 3.7 m/s | 3.7 |
| 2011 | 19.4°C | 15.9°C | 12.4°C | 23.4°C | 9.0°C | 43 mm | 84% | 4.3 m/s | 3.5 |
| 2010 | 17.9°C | 14.4°C | 10.9°C | 20.6°C | 5.9°C | 51 mm | 84% | 3.9 m/s | 3.5 |
| 2009 | 19.4°C | 15.7°C | 12.0°C | 22.7°C | 9.1°C | 30 mm | 80% | 3.9 m/s | 3.7 |
| 2008 | 17.6°C | 14.4°C | 11.2°C | 20.0°C | 7.8°C | 63 mm | 82% | 4 m/s | 3.4 |
| 2007 | 18.6°C | 14.8°C | 11.0°C | 22.5°C | 7.3°C | 27 mm | 83% | 3.6 m/s | 3.7 |
| 2006 | 21.3°C | 17.7°C | 14.1°C | 24.9°C | 10.2°C | 74 mm | 84% | 3.7 m/s | 3.5 |
| 2005 | 20.0°C | 16.3°C | 12.5°C | 24.7°C | 6.5°C | 46 mm | 83% | 3.2 m/s | 3.5 |
| 2004 | 19.3°C | 15.6°C | 12.0°C | 24.6°C | 7.0°C | 28 mm | 82% | 4.5 m/s | 3.5 |
| 2003 | 19.6°C | 15.3°C | 11.1°C | 23.6°C | 5.9°C | 13 mm | 78% | 2.7 m/s | 3.9 |
| 2002 | 18.5°C | 15.0°C | 11.6°C | 21.0°C | 8.0°C | 35 mm | 83% | 3.5 m/s | 3.8 |
| 2001 | 17.3°C | 14.0°C | 10.6°C | 20.0°C | 8.3°C | 72 mm | 84% | 4.2 m/s | 3.4 |
| 2000 | 18.7°C | 15.6°C | 12.5°C | 23.2°C | 8.3°C | 119 mm | 87% | 3.9 m/s | 2.9 |
| 1999 | 19.6°C | 16.5°C | 13.5°C | 24.3°C | 11.5°C | 113 mm | 86% | 3.8 m/s | 3.4 |
| 1998 | 18.7°C | 15.5°C | 12.3°C | 21.3°C | 7.5°C | 120 mm | 86% | 4.2 m/s | 3.4 |
| 1997 | 19.2°C | 15.4°C | 11.6°C | 22.8°C | 7.7°C | 12 mm | 82% | 3.4 m/s | 3.9 |
| 1996 | 17.8°C | 14.2°C | 10.7°C | 20.4°C | 7.5°C | 39 mm | 80% | 4.1 m/s | 3.5 |
| 1995 🌧️ | 17.7°C | 14.4°C | 11.1°C | 20.4°C | 6.2°C | 122 mm | 82% | 4 m/s | 3.2 |
| 1994 | 16.9°C | 13.8°C | 10.7°C | 19.9°C | 6.6°C | 85 mm | 85% | 4 m/s | 3.3 |
| 1993 | 16.4°C | 13.1°C | 9.9°C | 20.0°C | 6.4°C | 104 mm | 85% | 3.7 m/s | 3.1 |
| 1992 | 17.7°C | 14.3°C | 10.9°C | 21.2°C | 7.9°C | 75 mm | 85% | 4 m/s | 3.3 |
| 1991 | 20.0°C | 16.0°C | 12.0°C | 24.6°C | 7.4°C | 50 mm | 79% | 3.3 m/s | 3.6 |
| 1990 | 18.8°C | 14.6°C | 10.5°C | 23.6°C | 7.8°C | 33 mm | 75% | 3.7 m/s | 3.5 |
| 1989 | 20.0°C | 16.4°C | 12.7°C | 23.5°C | 9.2°C | 39 mm | 80% | 3.7 m/s | 3.4 |
| 1988 | 17.7°C | 14.3°C | 10.9°C | 21.5°C | 4.8°C | 60 mm | 84% | 4.3 m/s | 3.1 |
| 1987 | 18.3°C | 14.9°C | 11.4°C | 23.3°C | 6.2°C | 47 mm | 84% | 3.4 m/s | 3.1 |
| 1986 ❄️ | 16.3°C | 12.5°C | 8.7°C | 19.4°C | 6.2°C | 41 mm | 82% | 3.3 m/s | 3.2 |
| 1985 | 18.8°C | 15.0°C | 11.3°C | 22.6°C | 6.8°C | 19 mm | 84% | 3.4 m/s | 3.4 |
| 1984 | 17.8°C | 14.4°C | 11.0°C | 22.7°C | 7.9°C | 65 mm | 81% | 4.2 m/s | 3.1 |
| 1983 | 18.1°C | 14.7°C | 11.3°C | 22.9°C | 7.2°C | 70 mm | 83% | 4.6 m/s | — |
| 1982 | 19.6°C | 15.7°C | 11.8°C | 24.6°C | 8.2°C | 65 mm | 84% | 3.4 m/s | — |
| 1981 | 18.5°C | 15.2°C | 12.0°C | 21.8°C | 8.1°C | 111 mm | 83% | 3.9 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 18.8°C with lows near 11.6°C (mean 15.2°C), based on 45 years of NASA POWER data.
September averages 60 mm of rainfall in Brighton, about average for rainfall. The wettest on record was 122 mm in 1995.
The hottest September reached 28.9°C in 2023. The coldest dipped to 4.8°C in 1988.
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 18.6°C to 20.1°C and overnight lows from 11.5°C to 12.9°C over the same span.
September is one of the warmer months of the year in Brighton and about average for rainfall, so plan for around 18.8°C daytime highs and 11.6°C at night.
Not quite — September is the 10th coolest month in Brighton, averaging 15.2°C.
For September in Brighton, pack light layers you can adjust through the day, with typical highs of 18.8°C and lows of 11.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 83% — quite humid.
Average wind speed in September is 3.8 m/s. The windiest September on record averaged 4.7 m/s (2025).
The wettest September on record was 1995 with 122 mm. On average, September sees 60 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 Brighton 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.
