September is one of the warmer months of the year in Weymouth, with average highs near 17.5°C and lows around 14.3°C (mean 15.9°C). It is about average for rainfall, averaging 66 mm of rainfall and 82% relative humidity across the period.
September is one of the warmer months of the year in Weymouth. Across 45 years of records, the warmest September in Weymouth was 2023 — when the month averaged 17.9°C — while the coldest was 1986 at 13.6°C. Typical September days reach 17.5°C with nights near 14.3°C. The long-term trend is warming, about 0.3°C per decade.
September is about average for rainfall in Weymouth, averaging 66 mm of rainfall. The wettest September on record was 2024 with 149 mm, while the driest was 2014 at 11 mm.
Relative humidity in Weymouth during September averages 82%. The most humid September was 2006 at 87%, and the least humid was 1990 at 77%.
September receives about 3.3 kWh/m²/day of solar energy in Weymouth. The sunniest September was 2015 at 3.9 kWh/m²/day, and the cloudiest was 2000 at 2.8.
Average wind speed in Weymouth during September is 5.3 m/s. The windiest Septembers were 1983 and 2025 at 6.3 m/s, while the calmest was 2014 at 3.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 15.5°C | 15.6°C | 16.1°C | 15.9°C | 16.8°C | +1.3°C |
| Avg High | 17.1°C | 17.1°C | 17.7°C | 17.4°C | 18.5°C | +1.4°C |
| Avg Low | 13.9°C | 14.0°C | 14.5°C | 14.4°C | 15.1°C | +1.2°C |
| Avg Rain | 62 mm | 82 mm | 47 mm | 64 mm | 77 mm | +15 mm |
September temperatures in Weymouth have risen by about 1.2°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 9.1°C (2007) to a record high of 23.1°C (2023).
Rainfall in September is about average for rainfall, averaging 66 mm, with a wettest year of 149 mm.
One of the best times to visit Weymouth
September is one of the best times to visit Weymouth. Expect days averaging 17.5°C and nights around 14.3°C (mean 15.9°C) — warmer than Weymouth's yearly average — with moderate rainfall (66 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 | 17.8°C | 16.2°C | 14.6°C | 20.2°C | 11.4°C | 75 mm | 80% | 6.3 m/s | 3.5 |
| 2024 🌧️ | 17.8°C | 16.2°C | 14.6°C | 22.2°C | 11.2°C | 149 mm | 83% | 5.4 m/s | 3 |
| 2023 🔥 | 19.4°C | 17.9°C | 16.5°C | 23.1°C | 13.3°C | 68 mm | 86% | 4.6 m/s | 3.4 |
| 2022 | 18.7°C | 17.1°C | 15.4°C | 21.7°C | 12.5°C | 81 mm | 79% | 5.2 m/s | 3.3 |
| 2021 | 18.8°C | 17.1°C | 15.4°C | 22.6°C | 13.0°C | 56 mm | 85% | 4.6 m/s | 3.4 |
| 2020 | 18.3°C | 16.3°C | 14.2°C | 22.0°C | 10.7°C | 36 mm | 80% | 5.3 m/s | 3.5 |
| 2019 | 18.0°C | 16.4°C | 14.8°C | 19.5°C | 12.8°C | 101 mm | 81% | 6.1 m/s | 3.6 |
| 2018 | 17.7°C | 16.1°C | 14.5°C | 21.0°C | 10.8°C | 54 mm | 80% | 5.2 m/s | 3.4 |
| 2017 | 16.8°C | 15.4°C | 14.0°C | 18.7°C | 11.8°C | 127 mm | 84% | 5.8 m/s | 3.2 |
| 2016 | 18.2°C | 16.9°C | 15.5°C | 20.9°C | 13.8°C | 66 mm | 85% | 5.1 m/s | 3.2 |
| 2015 | 16.4°C | 14.9°C | 13.4°C | 18.4°C | 12.3°C | 56 mm | 81% | 5.6 m/s | 3.9 |
| 2014 | 18.8°C | 17.1°C | 15.4°C | 20.2°C | 13.4°C | 11 mm | 83% | 3.8 m/s | 3.5 |
| 2013 | 17.5°C | 15.8°C | 14.2°C | 20.3°C | 11.9°C | 53 mm | 84% | 4.8 m/s | 3.2 |
| 2012 | 16.6°C | 15.1°C | 13.5°C | 19.3°C | 10.4°C | 69 mm | 82% | 5.3 m/s | 3.6 |
| 2011 | 17.4°C | 16.1°C | 14.9°C | 19.0°C | 13.2°C | 46 mm | 85% | 6 m/s | 3.4 |
| 2010 | 16.9°C | 15.5°C | 14.1°C | 18.4°C | 9.9°C | 51 mm | 83% | 5.6 m/s | 3.4 |
| 2009 | 17.8°C | 15.8°C | 13.8°C | 19.3°C | 11.9°C | 27 mm | 82% | 5.4 m/s | 3.6 |
| 2008 | 16.7°C | 15.2°C | 13.8°C | 17.9°C | 12.1°C | 81 mm | 81% | 5.6 m/s | 3.5 |
| 2007 | 17.6°C | 15.7°C | 13.9°C | 21.0°C | 9.1°C | 38 mm | 83% | 5.1 m/s | 3.6 |
| 2006 | 18.7°C | 17.3°C | 15.9°C | 20.9°C | 14.3°C | 64 mm | 87% | 5.3 m/s | 3.4 |
| 2005 | 18.0°C | 16.5°C | 14.9°C | 20.1°C | 11.2°C | 36 mm | 84% | 4.8 m/s | 3.4 |
| 2004 | 17.8°C | 16.2°C | 14.5°C | 21.5°C | 11.8°C | 32 mm | 83% | 6.1 m/s | 3.6 |
| 2003 | 17.9°C | 16.3°C | 14.7°C | 20.0°C | 11.7°C | 21 mm | 79% | 4.2 m/s | 3.6 |
| 2002 | 17.8°C | 16.2°C | 14.5°C | 19.9°C | 12.0°C | 37 mm | 80% | 4.8 m/s | 3.6 |
| 2001 | 17.2°C | 15.4°C | 13.6°C | 19.2°C | 11.5°C | 41 mm | 81% | 5.8 m/s | 3.3 |
| 2000 | 17.5°C | 16.2°C | 15.0°C | 20.0°C | 12.6°C | 94 mm | 86% | 5.6 m/s | 2.8 |
| 1999 | 18.0°C | 16.7°C | 15.3°C | 21.8°C | 13.1°C | 122 mm | 85% | 5.3 m/s | 3.4 |
| 1998 | 17.5°C | 16.2°C | 14.8°C | 19.6°C | 10.6°C | 104 mm | 86% | 6 m/s | 3.2 |
| 1997 | 17.8°C | 16.2°C | 14.6°C | 19.3°C | 12.6°C | 20 mm | 83% | 4.8 m/s | 3.5 |
| 1996 | 17.0°C | 15.3°C | 13.6°C | 19.8°C | 11.4°C | 32 mm | 79% | 5.4 m/s | 3.4 |
| 1995 | 17.2°C | 15.5°C | 13.8°C | 20.0°C | 11.6°C | 130 mm | 81% | 5.8 m/s | 3.1 |
| 1994 | 16.3°C | 14.8°C | 13.3°C | 18.2°C | 10.5°C | 92 mm | 83% | 5.7 m/s | 3.1 |
| 1993 | 16.1°C | 14.7°C | 13.3°C | 20.4°C | 10.9°C | 107 mm | 80% | 5.2 m/s | 3 |
| 1992 | 16.1°C | 14.8°C | 13.4°C | 17.7°C | 11.2°C | 90 mm | 85% | 5.6 m/s | 3.2 |
| 1991 | 18.1°C | 16.3°C | 14.6°C | 21.2°C | 10.8°C | 78 mm | 82% | 4.7 m/s | 3.6 |
| 1990 | 17.3°C | 15.5°C | 13.6°C | 19.6°C | 11.0°C | 44 mm | 77% | 4.9 m/s | 3.5 |
| 1989 | 18.5°C | 16.7°C | 14.8°C | 21.0°C | 12.6°C | 45 mm | 80% | 5 m/s | 3.1 |
| 1988 | 16.4°C | 14.8°C | 13.2°C | 19.2°C | 10.6°C | 56 mm | 83% | 5.7 m/s | 3 |
| 1987 | 17.2°C | 15.7°C | 14.3°C | 20.3°C | 10.4°C | 51 mm | 83% | 4.6 m/s | 3 |
| 1986 ❄️ | 15.5°C | 13.6°C | 11.7°C | 16.9°C | 9.7°C | 44 mm | 80% | 4.4 m/s | 3.1 |
| 1985 | 16.8°C | 15.3°C | 13.8°C | 18.4°C | 11.4°C | 30 mm | 87% | 4.6 m/s | 3.2 |
| 1984 | 17.1°C | 15.4°C | 13.7°C | 19.7°C | 11.0°C | 70 mm | 79% | 5.9 m/s | 3.2 |
| 1983 | 16.9°C | 15.4°C | 13.9°C | 22.0°C | 11.5°C | 71 mm | 84% | 6.3 m/s | — |
| 1982 | 17.7°C | 16.2°C | 14.7°C | 21.8°C | 11.7°C | 62 mm | 84% | 4.5 m/s | — |
| 1981 | 17.5°C | 16.1°C | 14.8°C | 19.4°C | 12.1°C | 131 mm | 82% | 5.4 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.5°C with lows near 14.3°C (mean 15.9°C), based on 45 years of NASA POWER data.
September averages 66 mm of rainfall in Weymouth, about average for rainfall. The wettest on record was 149 mm in 2024.
The hottest September reached 23.1°C in 2023. The coldest dipped to 9.1°C in 2007.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.2°C. Daytime highs moved from 17.2°C to 18.5°C and overnight lows from 14.2°C to 15.3°C over the same span.
September is one of the warmer months of the year in Weymouth and about average for rainfall, so plan for around 17.5°C daytime highs and 14.3°C at night.
Not quite — September is the 10th coolest month in Weymouth, averaging 15.9°C.
For September in Weymouth, pack light layers you can adjust through the day, with typical highs of 17.5°C and lows of 14.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 82% — quite humid.
Average wind speed in September is 5.3 m/s. The windiest September on record averaged 6.3 m/s (1983).
The wettest September on record was 2024 with 149 mm. On average, September sees 66 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 Weymouth 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.
