September is one of the warmer months of the year in Lancaster, with average highs near 15.8°C and lows around 9.1°C (mean 12.5°C). It is about average for rainfall, averaging 93 mm of rainfall and 88% relative humidity across the period.
September is one of the warmer months of the year in Lancaster. Across 45 years of records, the warmest September in Lancaster was 2023 — when the month averaged 14.9°C — while the coldest was 1986 at 10.1°C. Typical September days reach 15.8°C with nights near 9.1°C. The long-term trend is warming, about 0.3°C per decade.
September is about average for rainfall in Lancaster, averaging 93 mm of rainfall. The wettest September on record was 2025 with 164 mm, while the driest was 1986 at 20 mm.
Relative humidity in Lancaster during September averages 88%. The most humid September was 1985 at 90%, and the least humid was 1991 at 84%.
September receives about 2.8 kWh/m²/day of solar energy in Lancaster. The sunniest September was 2015 at 3.3 kWh/m²/day, and the cloudiest were 2000, 2001 and 2008, among others at 2.4.
Average wind speed in Lancaster during September is 3.4 m/s. The windiest September was 1983 at 4.3 m/s, while the calmest was 2014 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.9°C | 12.0°C | 12.8°C | 12.4°C | 13.3°C | +1.4°C |
| Avg High | 15.0°C | 15.4°C | 16.1°C | 15.8°C | 16.8°C | +1.8°C |
| Avg Low | 8.7°C | 8.7°C | 9.4°C | 9.1°C | 9.8°C | +1.1°C |
| Avg Rain | 94 mm | 83 mm | 92 mm | 96 mm | 103 mm | +9 mm |
September temperatures in Lancaster have risen by about 1.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 1.7°C (1986) to a record high of 24.4°C (2021).
Rainfall in September is about average for rainfall, averaging 93 mm, with a wettest year of 164 mm.
One of the best times to visit Lancaster
September is one of the best times to visit Lancaster. Expect days averaging 15.8°C and nights around 9.1°C (mean 12.5°C) — warmer than Lancaster's yearly average — with higher rainfall (93 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 🌧️ | 15.9°C | 12.5°C | 9.2°C | 19.0°C | 3.5°C | 164 mm | 88% | 3.5 m/s | 2.7 |
| 2024 | 15.8°C | 12.5°C | 9.1°C | 21.9°C | 3.9°C | 95 mm | 88% | 3.5 m/s | 2.8 |
| 2023 🔥 | 18.4°C | 14.9°C | 11.4°C | 24.0°C | 6.4°C | 129 mm | 88% | 3.2 m/s | 2.8 |
| 2022 | 16.7°C | 13.0°C | 9.3°C | 21.2°C | 3.8°C | 96 mm | 87% | 2.9 m/s | 2.8 |
| 2021 | 18.1°C | 14.6°C | 11.0°C | 24.4°C | 8.0°C | 65 mm | 88% | 2.7 m/s | 2.8 |
| 2020 | 15.9°C | 12.3°C | 8.6°C | 22.2°C | 3.7°C | 65 mm | 87% | 3.4 m/s | 2.8 |
| 2019 | 15.7°C | 12.5°C | 9.4°C | 19.3°C | 5.2°C | 133 mm | 88% | 3.4 m/s | 2.8 |
| 2018 | 15.2°C | 11.9°C | 8.6°C | 20.8°C | 2.8°C | 87 mm | 86% | 3.8 m/s | 2.7 |
| 2017 | 15.1°C | 12.1°C | 9.1°C | 20.1°C | 5.4°C | 127 mm | 90% | 3.4 m/s | 2.5 |
| 2016 | 17.5°C | 14.3°C | 11.0°C | 22.8°C | 8.2°C | 83 mm | 89% | 3.5 m/s | 2.7 |
| 2015 | 15.2°C | 11.3°C | 7.4°C | 18.3°C | 5.4°C | 47 mm | 87% | 2.7 m/s | 3.3 |
| 2014 | 17.6°C | 13.4°C | 9.1°C | 20.4°C | 5.9°C | 21 mm | 87% | 2.1 m/s | 3 |
| 2013 | 15.4°C | 12.1°C | 8.8°C | 20.3°C | 5.8°C | 67 mm | 88% | 3.3 m/s | 2.5 |
| 2012 | 14.1°C | 11.1°C | 8.1°C | 19.7°C | 2.6°C | 154 mm | 89% | 3.9 m/s | 2.7 |
| 2011 | 16.1°C | 13.2°C | 10.2°C | 22.4°C | 6.9°C | 112 mm | 88% | 4.1 m/s | 2.7 |
| 2010 | 15.8°C | 12.5°C | 9.1°C | 19.3°C | 3.1°C | 125 mm | 87% | 3.7 m/s | 2.8 |
| 2009 | 15.6°C | 12.6°C | 9.6°C | 20.6°C | 6.0°C | 55 mm | 89% | 3.5 m/s | 2.7 |
| 2008 | 15.3°C | 12.2°C | 9.0°C | 18.2°C | 6.6°C | 118 mm | 90% | 3 m/s | 2.4 |
| 2007 | 15.5°C | 12.0°C | 8.6°C | 19.9°C | 2.6°C | 77 mm | 89% | 3.5 m/s | 2.8 |
| 2006 | 18.4°C | 14.8°C | 11.2°C | 23.2°C | 6.8°C | 94 mm | 88% | 3.3 m/s | 2.9 |
| 2005 | 16.7°C | 13.4°C | 10.1°C | 22.4°C | 5.5°C | 94 mm | 87% | 3.5 m/s | 2.8 |
| 2004 | 16.0°C | 12.9°C | 9.8°C | 22.3°C | 5.3°C | 93 mm | 89% | 4.2 m/s | 2.9 |
| 2003 | 16.3°C | 12.6°C | 8.8°C | 20.4°C | 5.3°C | 90 mm | 87% | 2.4 m/s | 2.9 |
| 2002 | 16.4°C | 12.8°C | 9.1°C | 19.8°C | 5.9°C | 48 mm | 87% | 2.3 m/s | 3 |
| 2001 | 15.0°C | 11.8°C | 8.6°C | 18.6°C | 5.8°C | 92 mm | 89% | 3.7 m/s | 2.4 |
| 2000 | 16.2°C | 12.9°C | 9.6°C | 22.7°C | 4.3°C | 161 mm | 90% | 3.2 m/s | 2.4 |
| 1999 | 17.3°C | 13.8°C | 10.3°C | 23.1°C | 6.4°C | 112 mm | 88% | 3.1 m/s | 2.8 |
| 1998 | 16.2°C | 13.0°C | 9.8°C | 21.7°C | 5.6°C | 89 mm | 90% | 3.3 m/s | 2.9 |
| 1997 | 15.4°C | 12.2°C | 8.9°C | 17.9°C | 5.7°C | 60 mm | 88% | 3.5 m/s | 2.9 |
| 1996 | 15.7°C | 12.0°C | 8.4°C | 20.9°C | 5.4°C | 43 mm | 86% | 3.4 m/s | 2.8 |
| 1995 | 15.4°C | 11.9°C | 8.5°C | 18.9°C | 3.8°C | 102 mm | 87% | 2.9 m/s | 2.7 |
| 1994 | 13.7°C | 10.7°C | 7.7°C | 17.2°C | 5.0°C | 111 mm | 89% | 3.5 m/s | 2.8 |
| 1993 | 14.4°C | 10.9°C | 7.3°C | 19.6°C | 2.8°C | 82 mm | 87% | 3.5 m/s | 2.4 |
| 1992 | 14.8°C | 11.8°C | 8.7°C | 21.1°C | 5.3°C | 102 mm | 88% | 3.9 m/s | 2.9 |
| 1991 | 16.8°C | 12.7°C | 8.7°C | 23.0°C | 3.1°C | 58 mm | 84% | 3.4 m/s | 3.2 |
| 1990 | 14.5°C | 11.4°C | 8.3°C | 18.7°C | 5.2°C | 71 mm | 85% | 3.5 m/s | 2.5 |
| 1989 | 15.9°C | 12.5°C | 9.1°C | 20.2°C | 5.9°C | 31 mm | 87% | 3.2 m/s | 2.6 |
| 1988 | 14.2°C | 11.5°C | 8.7°C | 22.5°C | 2.2°C | 97 mm | 88% | 4 m/s | 2.4 |
| 1987 | 14.6°C | 11.6°C | 8.7°C | 19.1°C | 3.1°C | 111 mm | 88% | 3.5 m/s | 2.8 |
| 1986 ❄️ | 13.8°C | 10.1°C | 6.3°C | 18.0°C | 1.7°C | 20 mm | 85% | 2.8 m/s | 3.2 |
| 1985 | 15.7°C | 12.6°C | 9.5°C | 20.1°C | 5.8°C | 99 mm | 90% | 3.5 m/s | 2.6 |
| 1984 | 14.7°C | 11.8°C | 8.9°C | 20.0°C | 4.2°C | 148 mm | 86% | 3.4 m/s | 2.6 |
| 1983 | 14.5°C | 11.5°C | 8.6°C | 17.8°C | 4.3°C | 113 mm | 87% | 4.3 m/s | — |
| 1982 | 16.0°C | 12.5°C | 9.1°C | 22.3°C | 4.8°C | 93 mm | 87% | 3.5 m/s | — |
| 1981 | 15.9°C | 12.8°C | 9.6°C | 20.5°C | 6.1°C | 133 mm | 87% | 3.6 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 15.8°C with lows near 9.1°C (mean 12.5°C), based on 45 years of NASA POWER data.
September averages 93 mm of rainfall in Lancaster, about average for rainfall. The wettest on record was 164 mm in 2025.
The hottest September reached 24.4°C in 2021. The coldest dipped to 1.7°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.3°C. Daytime highs moved from 15.4°C to 17°C and overnight lows from 9.1°C to 10°C over the same span.
September is one of the warmer months of the year in Lancaster and about average for rainfall, so plan for around 15.8°C daytime highs and 9.1°C at night.
Not quite — September is the 9th coolest month in Lancaster, averaging 12.5°C.
For September in Lancaster, pack light layers you can adjust through the day, with typical highs of 15.8°C and lows of 9.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 88% — quite humid.
Average wind speed in September is 3.4 m/s. The windiest September on record averaged 4.3 m/s (1983).
The wettest September on record was 2025 with 164 mm. On average, September sees 93 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 Lancaster 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.
