September is one of the warmer months of the year in Falmouth, with average highs near 16.8°C and lows around 14.3°C (mean 15.6°C). It is one of the drier months, averaging 72 mm of rainfall and 85% relative humidity across the period.
September is one of the warmer months of the year in Falmouth. Across 45 years of records, the warmest September in Falmouth was 2023 — when the month averaged 17.4°C — while the coldest was 1986 at 13.2°C. Typical September days reach 16.8°C with nights near 14.3°C. The long-term trend is warming, about 0.2°C per decade.
September is one of the drier months in Falmouth, averaging 72 mm of rainfall. The wettest September on record was 1993 with 142 mm, while the driest was 2014 at 8 mm.
Relative humidity in Falmouth during September averages 85%. The most humid September was 2006 at 89%, and the least humid was 1990 at 80%.
September receives about 3.4 kWh/m²/day of solar energy in Falmouth. The sunniest Septembers were 1996 and 2014 at 3.9 kWh/m²/day, and the cloudiest was 2000 at 2.9.
Average wind speed in Falmouth during September is 5.5 m/s. The windiest Septembers were 2017 and 2019 at 6.6 m/s, while the calmest was 2014 at 4.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 15.1°C | 15.2°C | 15.7°C | 15.5°C | 16.2°C | +1.1°C |
| Avg High | 16.4°C | 16.5°C | 17.0°C | 16.7°C | 17.5°C | +1.1°C |
| Avg Low | 13.9°C | 14.0°C | 14.4°C | 14.3°C | 15.0°C | +1.1°C |
| Avg Rain | 74 mm | 83 mm | 52 mm | 71 mm | 89 mm | +15 mm |
September temperatures in Falmouth have risen by about 1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 10.2°C (2007) to a record high of 22°C (2023).
Rainfall in September is one of the drier months, averaging 72 mm, with a wettest year of 142 mm.
One of the best times to visit Falmouth
September is one of the best times to visit Falmouth. Expect days averaging 16.8°C and nights around 14.3°C (mean 15.6°C) — warmer than Falmouth's yearly average — with moderate rainfall (72 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 | 16.8°C | 15.6°C | 14.4°C | 19.0°C | 11.5°C | 90 mm | 83% | 6.2 m/s | 3.5 |
| 2024 | 16.9°C | 15.6°C | 14.4°C | 19.5°C | 11.8°C | 93 mm | 84% | 5.8 m/s | 3 |
| 2023 🔥 | 18.6°C | 17.4°C | 16.1°C | 22.0°C | 13.8°C | 93 mm | 88% | 5.2 m/s | 3.4 |
| 2022 | 17.6°C | 16.4°C | 15.2°C | 20.4°C | 12.9°C | 105 mm | 83% | 5.9 m/s | 3.3 |
| 2021 | 18.0°C | 16.7°C | 15.3°C | 20.9°C | 13.3°C | 75 mm | 88% | 4.7 m/s | 3.1 |
| 2020 | 17.1°C | 15.7°C | 14.4°C | 19.9°C | 11.6°C | 76 mm | 84% | 5.3 m/s | 3.4 |
| 2019 | 17.1°C | 15.9°C | 14.8°C | 18.2°C | 13.6°C | 106 mm | 85% | 6.6 m/s | 3.5 |
| 2018 | 16.9°C | 15.6°C | 14.3°C | 19.9°C | 11.9°C | 56 mm | 83% | 5.4 m/s | 3.4 |
| 2017 | 16.1°C | 15.0°C | 13.9°C | 18.4°C | 12.2°C | 123 mm | 85% | 6.6 m/s | 3.3 |
| 2016 | 17.3°C | 16.3°C | 15.3°C | 19.5°C | 13.3°C | 85 mm | 87% | 5.8 m/s | 3.1 |
| 2015 | 15.6°C | 14.5°C | 13.4°C | 17.7°C | 12.4°C | 56 mm | 83% | 5.8 m/s | 3.8 |
| 2014 | 18.0°C | 16.5°C | 15.1°C | 19.3°C | 13.6°C | 8 mm | 87% | 4.1 m/s | 3.9 |
| 2013 | 16.7°C | 15.5°C | 14.2°C | 18.6°C | 12.6°C | 58 mm | 86% | 5.3 m/s | 3 |
| 2012 | 16.0°C | 14.8°C | 13.6°C | 18.5°C | 11.3°C | 70 mm | 82% | 5.3 m/s | 3.4 |
| 2011 | 16.6°C | 15.5°C | 14.4°C | 18.1°C | 13.1°C | 60 mm | 87% | 6.4 m/s | 3.3 |
| 2010 | 16.5°C | 15.3°C | 14.1°C | 18.4°C | 11.1°C | 86 mm | 84% | 5.4 m/s | 3.5 |
| 2009 | 16.6°C | 15.2°C | 13.8°C | 17.7°C | 12.5°C | 35 mm | 85% | 5.3 m/s | 3.6 |
| 2008 | 16.1°C | 14.9°C | 13.8°C | 17.0°C | 12.5°C | 79 mm | 84% | 5.6 m/s | 3.5 |
| 2007 | 17.0°C | 15.6°C | 14.1°C | 20.2°C | 10.2°C | 34 mm | 83% | 5.1 m/s | 3.7 |
| 2006 | 18.1°C | 16.8°C | 15.6°C | 20.0°C | 14.4°C | 50 mm | 89% | 5.8 m/s | 3.5 |
| 2005 | 17.5°C | 16.2°C | 15.0°C | 19.8°C | 12.2°C | 59 mm | 84% | 5.2 m/s | 3.4 |
| 2004 | 16.9°C | 15.7°C | 14.6°C | 20.8°C | 12.3°C | 44 mm | 85% | 6.4 m/s | 3.5 |
| 2003 | 17.2°C | 15.8°C | 14.4°C | 19.2°C | 11.8°C | 30 mm | 83% | 4.7 m/s | 3.6 |
| 2002 | 17.0°C | 15.6°C | 14.2°C | 19.4°C | 12.4°C | 29 mm | 84% | 5 m/s | 3.8 |
| 2001 | 16.4°C | 15.2°C | 14.0°C | 18.2°C | 12.3°C | 37 mm | 84% | 5.9 m/s | 3.5 |
| 2000 | 17.0°C | 15.8°C | 14.7°C | 19.8°C | 12.4°C | 119 mm | 87% | 5.6 m/s | 2.9 |
| 1999 | 17.5°C | 16.3°C | 15.0°C | 20.3°C | 13.3°C | 107 mm | 85% | 5.6 m/s | 3.5 |
| 1998 | 16.8°C | 15.7°C | 14.7°C | 18.7°C | 12.8°C | 98 mm | 88% | 6.3 m/s | 3.3 |
| 1997 | 17.1°C | 15.7°C | 14.4°C | 18.6°C | 12.9°C | 30 mm | 87% | 5.1 m/s | 3.5 |
| 1996 | 16.4°C | 14.9°C | 13.4°C | 19.0°C | 11.2°C | 43 mm | 84% | 5.5 m/s | 3.9 |
| 1995 | 16.4°C | 15.2°C | 14.0°C | 18.9°C | 11.7°C | 97 mm | 83% | 5.9 m/s | 3.5 |
| 1994 | 15.4°C | 14.2°C | 13.0°C | 17.2°C | 11.2°C | 107 mm | 85% | 6.1 m/s | 3.1 |
| 1993 🌧️ | 15.5°C | 14.3°C | 13.2°C | 18.9°C | 11.0°C | 142 mm | 83% | 5.7 m/s | 3.4 |
| 1992 | 15.2°C | 14.1°C | 13.0°C | 17.5°C | 11.2°C | 105 mm | 87% | 5.9 m/s | 3.2 |
| 1991 | 17.5°C | 16.2°C | 14.8°C | 20.8°C | 11.6°C | 58 mm | 84% | 4.9 m/s | 3.6 |
| 1990 | 16.9°C | 15.4°C | 14.0°C | 20.1°C | 12.2°C | 45 mm | 80% | 5.3 m/s | 3.7 |
| 1989 | 17.5°C | 16.1°C | 14.7°C | 20.1°C | 12.3°C | 56 mm | 83% | 5.2 m/s | 3 |
| 1988 | 15.5°C | 14.4°C | 13.3°C | 17.9°C | 10.5°C | 58 mm | 85% | 5.9 m/s | 3.2 |
| 1987 | 16.8°C | 15.6°C | 14.4°C | 19.0°C | 11.6°C | 70 mm | 84% | 4.8 m/s | 3.4 |
| 1986 ❄️ | 14.7°C | 13.2°C | 11.7°C | 16.0°C | 10.3°C | 40 mm | 83% | 4.3 m/s | 3.4 |
| 1985 | 16.4°C | 15.2°C | 13.9°C | 18.1°C | 12.0°C | 43 mm | 88% | 5 m/s | 3.4 |
| 1984 | 16.5°C | 15.2°C | 14.0°C | 20.0°C | 11.4°C | 99 mm | 80% | 6.1 m/s | 3.4 |
| 1983 | 16.0°C | 14.8°C | 13.7°C | 18.7°C | 11.7°C | 96 mm | 86% | 6.5 m/s | — |
| 1982 | 16.9°C | 15.6°C | 14.4°C | 20.0°C | 11.7°C | 75 mm | 87% | 4.8 m/s | — |
| 1981 | 17.2°C | 15.9°C | 14.7°C | 19.0°C | 12.1°C | 130 mm | 84% | 5.8 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 16.8°C with lows near 14.3°C (mean 15.6°C), based on 45 years of NASA POWER data.
September averages 72 mm of rainfall in Falmouth, one of the drier months. The wettest on record was 142 mm in 1993.
The hottest September reached 22°C in 2023. The coldest dipped to 10.2°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°C. Daytime highs moved from 16.6°C to 17.6°C and overnight lows from 14.1°C to 15.1°C over the same span.
September is one of the warmer months of the year in Falmouth and one of the drier months, so plan for around 16.8°C daytime highs and 14.3°C at night.
Not quite — September is the 10th coolest month in Falmouth, averaging 15.6°C.
For September in Falmouth, pack light layers you can adjust through the day, with typical highs of 16.8°C and lows of 14.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 85% — quite humid.
Average wind speed in September is 5.5 m/s. The windiest September on record averaged 6.6 m/s (2017).
The wettest September on record was 1993 with 142 mm. On average, September sees 72 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 Falmouth 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.
