September is one of the warmer months of the year in Neath, with average highs near 17.2°C and lows around 12.3°C (mean 14.8°C). It is about average for rainfall, averaging 87 mm of rainfall and 85% relative humidity across the period.
September is one of the warmer months of the year in Neath. Across 45 years of records, the warmest September in Neath was 2023 — when the month averaged 17.2°C — while the coldest was 1986 at 12.3°C. Typical September days reach 17.2°C with nights near 12.3°C. The long-term trend is warming, about 0.2°C per decade.
September is about average for rainfall in Neath, averaging 87 mm of rainfall. The wettest September on record was 1981 with 161 mm, while the driest was 2014 at 20 mm.
Relative humidity in Neath during September averages 85%. The most humid September was 1998 at 88%, and the least humid was 1990 at 81%.
September receives about 3.2 kWh/m²/day of solar energy in Neath. 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 Neath during September is 4.2 m/s. The windiest September was 1983 at 5.3 m/s, while the calmest was 2014 at 3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.4°C | 14.4°C | 15.0°C | 14.7°C | 15.5°C | +1.1°C |
| Avg High | 16.7°C | 16.9°C | 17.5°C | 17.1°C | 18.0°C | +1.3°C |
| Avg Low | 12.0°C | 11.9°C | 12.5°C | 12.3°C | 13.1°C | +1.1°C |
| Avg Rain | 91 mm | 88 mm | 66 mm | 93 mm | 101 mm | +10 mm |
September temperatures in Neath have risen by about 0.9°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 6.1°C (1986) to a record high of 25°C (2023).
Rainfall in September is about average for rainfall, averaging 87 mm, with a wettest year of 161 mm.
One of the best times to visit Neath
September is one of the best times to visit Neath. Expect days averaging 17.2°C and nights around 12.3°C (mean 14.8°C) — warmer than Neath's yearly average — with higher rainfall (87 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 | 17.1°C | 14.7°C | 12.4°C | 20.0°C | 7.8°C | 134 mm | 84% | 4.7 m/s | 3.3 |
| 2024 | 17.1°C | 14.7°C | 12.4°C | 21.3°C | 8.6°C | 143 mm | 86% | 4.1 m/s | 2.7 |
| 2023 🔥 | 19.7°C | 17.2°C | 14.7°C | 25.0°C | 10.5°C | 92 mm | 86% | 3.9 m/s | 3.2 |
| 2022 | 17.9°C | 15.4°C | 13.0°C | 21.7°C | 9.8°C | 91 mm | 84% | 4 m/s | 3.1 |
| 2021 | 18.9°C | 16.2°C | 13.6°C | 24.1°C | 10.8°C | 86 mm | 86% | 3.4 m/s | 3.2 |
| 2020 | 17.5°C | 14.8°C | 12.2°C | 22.4°C | 8.5°C | 57 mm | 84% | 4.2 m/s | 3.5 |
| 2019 | 17.5°C | 15.1°C | 12.7°C | 21.2°C | 9.4°C | 160 mm | 85% | 4.7 m/s | 3.4 |
| 2018 | 16.9°C | 14.5°C | 12.1°C | 20.5°C | 8.4°C | 95 mm | 84% | 4.3 m/s | 3.1 |
| 2017 | 16.5°C | 14.4°C | 12.2°C | 19.1°C | 10.0°C | 128 mm | 87% | 4.7 m/s | 2.9 |
| 2016 | 18.1°C | 15.9°C | 13.6°C | 22.1°C | 10.9°C | 105 mm | 87% | 4.3 m/s | 3 |
| 2015 | 16.2°C | 13.5°C | 10.9°C | 19.3°C | 8.6°C | 72 mm | 85% | 4.1 m/s | 3.6 |
| 2014 | 18.5°C | 15.7°C | 12.8°C | 20.9°C | 10.1°C | 20 mm | 85% | 3 m/s | 3.4 |
| 2013 | 17.1°C | 14.6°C | 12.0°C | 20.4°C | 10.2°C | 76 mm | 86% | 3.9 m/s | 3 |
| 2012 | 15.7°C | 13.5°C | 11.3°C | 19.1°C | 7.7°C | 92 mm | 86% | 4.5 m/s | 3.4 |
| 2011 | 17.3°C | 15.1°C | 13.0°C | 21.5°C | 11.2°C | 86 mm | 87% | 5 m/s | 3.1 |
| 2010 | 16.9°C | 14.5°C | 12.0°C | 19.6°C | 7.3°C | 95 mm | 86% | 4.3 m/s | 3 |
| 2009 | 17.1°C | 14.4°C | 11.7°C | 20.3°C | 9.6°C | 37 mm | 85% | 4.1 m/s | 3.4 |
| 2008 | 16.6°C | 14.2°C | 11.9°C | 18.3°C | 9.5°C | 105 mm | 85% | 4 m/s | 3 |
| 2007 | 17.2°C | 14.7°C | 12.1°C | 20.9°C | 6.9°C | 51 mm | 86% | 4.2 m/s | 3.3 |
| 2006 | 19.1°C | 16.5°C | 14.0°C | 21.3°C | 11.1°C | 59 mm | 87% | 4.3 m/s | 3.2 |
| 2005 | 18.1°C | 15.4°C | 12.7°C | 22.3°C | 9.2°C | 71 mm | 86% | 4 m/s | 3.3 |
| 2004 | 17.5°C | 15.3°C | 13.0°C | 23.4°C | 10.5°C | 71 mm | 85% | 5.1 m/s | 3.3 |
| 2003 | 17.8°C | 15.0°C | 12.3°C | 21.1°C | 8.9°C | 33 mm | 83% | 3.3 m/s | 3.4 |
| 2002 | 17.7°C | 14.9°C | 12.1°C | 21.0°C | 9.5°C | 40 mm | 84% | 3.5 m/s | 3.4 |
| 2001 | 16.5°C | 14.2°C | 11.9°C | 19.3°C | 9.2°C | 56 mm | 85% | 4.5 m/s | 2.9 |
| 2000 | 17.6°C | 15.4°C | 13.2°C | 22.0°C | 9.7°C | 141 mm | 87% | 4.1 m/s | 2.6 |
| 1999 | 18.0°C | 15.6°C | 13.2°C | 22.6°C | 10.8°C | 131 mm | 86% | 4 m/s | 3.3 |
| 1998 | 17.4°C | 15.2°C | 12.9°C | 20.7°C | 9.7°C | 111 mm | 88% | 4.6 m/s | 3.1 |
| 1997 | 17.7°C | 14.9°C | 12.2°C | 20.7°C | 10.3°C | 42 mm | 86% | 4.1 m/s | 3.3 |
| 1996 | 17.1°C | 14.3°C | 11.5°C | 20.6°C | 9.3°C | 41 mm | 82% | 4.2 m/s | 3.3 |
| 1995 | 16.4°C | 14.2°C | 12.1°C | 19.8°C | 9.4°C | 96 mm | 84% | 4.2 m/s | 3 |
| 1994 | 15.6°C | 13.4°C | 11.3°C | 18.2°C | 8.6°C | 118 mm | 86% | 4.6 m/s | 3 |
| 1993 | 15.8°C | 13.3°C | 10.9°C | 20.4°C | 7.7°C | 103 mm | 84% | 4 m/s | 2.8 |
| 1992 | 15.8°C | 13.6°C | 11.5°C | 18.9°C | 9.1°C | 107 mm | 86% | 4.6 m/s | 3.1 |
| 1991 | 18.3°C | 15.5°C | 12.7°C | 22.7°C | 9.5°C | 73 mm | 82% | 4 m/s | 3.6 |
| 1990 | 16.7°C | 13.9°C | 11.1°C | 20.2°C | 7.6°C | 61 mm | 81% | 4 m/s | 3.3 |
| 1989 | 17.7°C | 15.2°C | 12.6°C | 21.1°C | 10.2°C | 74 mm | 84% | 3.9 m/s | 2.9 |
| 1988 | 16.0°C | 13.7°C | 11.5°C | 21.7°C | 8.0°C | 84 mm | 85% | 4.7 m/s | 2.9 |
| 1987 | 16.8°C | 14.5°C | 12.2°C | 19.8°C | 7.8°C | 78 mm | 85% | 4.1 m/s | 3 |
| 1986 ❄️ | 15.0°C | 12.3°C | 9.6°C | 17.1°C | 6.1°C | 25 mm | 83% | 3.4 m/s | 3.4 |
| 1985 | 17.3°C | 14.8°C | 12.3°C | 20.2°C | 9.1°C | 61 mm | 87% | 4 m/s | 3.2 |
| 1984 | 16.4°C | 14.3°C | 12.1°C | 21.3°C | 9.4°C | 128 mm | 82% | 4.8 m/s | 3.1 |
| 1983 | 16.6°C | 14.4°C | 12.3°C | 20.4°C | 9.4°C | 113 mm | 85% | 5.3 m/s | — |
| 1982 | 17.5°C | 14.9°C | 12.4°C | 23.0°C | 9.9°C | 92 mm | 87% | 3.7 m/s | — |
| 1981 🌧️ | 17.3°C | 15.1°C | 12.8°C | 20.2°C | 10.6°C | 161 mm | 84% | 4.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.2°C with lows near 12.3°C (mean 14.8°C), based on 45 years of NASA POWER data.
September averages 87 mm of rainfall in Neath, about average for rainfall. The wettest on record was 161 mm in 1981.
The hottest September reached 25°C in 2023. The coldest dipped to 6.1°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.9°C. Daytime highs moved from 17°C to 18.1°C and overnight lows from 12.4°C to 13.2°C over the same span.
September is one of the warmer months of the year in Neath and about average for rainfall, so plan for around 17.2°C daytime highs and 12.3°C at night.
Not quite — September is the 10th coolest month in Neath, averaging 14.8°C.
For September in Neath, pack light layers you can adjust through the day, with typical highs of 17.2°C and lows of 12.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 85% — quite humid.
Average wind speed in September is 4.2 m/s. The windiest September on record averaged 5.3 m/s (1983).
The wettest September on record was 1981 with 161 mm. On average, September sees 87 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 Neath 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.
