September is one of the warmer months of the year in Lancaster, with average highs near 25.4°C and lows around 13.7°C (mean 19.5°C). It is a relatively wet time of year, averaging 112 mm of rainfall and 72% 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 2019 — when the month averaged 22.3°C — while the coldest was 1984 at 17.3°C. Typical September days reach 25.4°C with nights near 13.7°C. The long-term trend is warming, about 0.5°C per decade.
September is a relatively wet time of year in Lancaster, averaging 112 mm of rainfall. The wettest September on record was 2011 with 312 mm, while the driest were 2005 and 2019 at 20 mm.
Relative humidity in Lancaster during September averages 72%. The most humid September was 2011 at 88%, and the least humid was 1983 at 58%.
September receives about 4.2 kWh/m²/day of solar energy in Lancaster. The sunniest September was 2007 at 5.1 kWh/m²/day, and the cloudiest were 2011 and 2018 at 3.1.
Average wind speed in Lancaster during September is 1 m/s. The windiest September was 1999 at 1.2 m/s, while the calmest were 2020, 2024 and 2025, among others at 0.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 18.9°C | 18.9°C | 19.4°C | 20.5°C | 20.3°C | +1.4°C |
| Avg High | 25.0°C | 24.8°C | 25.2°C | 26.2°C | 26.1°C | +1.1°C |
| Avg Low | 12.8°C | 13.0°C | 13.6°C | 14.7°C | 14.6°C | +1.8°C |
| Avg Rain | 92 mm | 116 mm | 118 mm | 122 mm | 110 mm | +18 mm |
September temperatures in Lancaster have risen by about 1.4°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 2.6°C (2000) to a record high of 36.9°C (2023).
Rainfall in September is a relatively wet time of year, averaging 112 mm, with a wettest year of 312 mm.
One of the best times to visit Lancaster
September is one of the best times to visit Lancaster. Expect days averaging 25.4°C and nights around 13.7°C (mean 19.5°C) — warmer than Lancaster's yearly average — with higher rainfall (112 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 | 27.7°C | 21.5°C | 15.2°C | 32.0°C | 10.2°C | 71 mm | 65% | 0.9 m/s | 4.5 |
| 2024 | 26.4°C | 20.6°C | 14.9°C | 31.0°C | 8.9°C | 49 mm | 72% | 0.9 m/s | 4.1 |
| 2023 | 26.6°C | 20.8°C | 15.0°C | 36.9°C | 8.7°C | 137 mm | 72% | 1 m/s | 4.2 |
| 2022 | 25.6°C | 20.0°C | 14.3°C | 32.1°C | 6.9°C | 104 mm | 71% | 1 m/s | 4.2 |
| 2021 | 24.6°C | 19.6°C | 14.7°C | 29.0°C | 9.1°C | 222 mm | 82% | 1 m/s | 4.3 |
| 2020 | 25.4°C | 19.4°C | 13.4°C | 29.7°C | 3.9°C | 80 mm | 72% | 0.9 m/s | 4.1 |
| 2019 🔥 | 28.8°C | 22.3°C | 15.7°C | 35.0°C | 8.9°C | 20 mm | 64% | 0.9 m/s | 4.3 |
| 2018 | 25.2°C | 21.0°C | 16.8°C | 32.1°C | 9.8°C | 208 mm | 87% | 0.9 m/s | 3.1 |
| 2017 | 25.8°C | 20.0°C | 14.2°C | 33.2°C | 8.0°C | 60 mm | 72% | 0.9 m/s | 4.3 |
| 2016 | 27.9°C | 21.7°C | 15.5°C | 34.6°C | 8.6°C | 109 mm | 65% | 1.1 m/s | 4.6 |
| 2015 | 27.4°C | 21.3°C | 15.1°C | 35.0°C | 9.7°C | 119 mm | 69% | 0.9 m/s | 4.6 |
| 2014 | 26.1°C | 20.0°C | 13.8°C | 32.3°C | 7.1°C | 52 mm | 68% | 0.9 m/s | 4.4 |
| 2013 | 25.2°C | 18.6°C | 11.9°C | 34.6°C | 4.7°C | 43 mm | 67% | 0.9 m/s | 4.8 |
| 2012 | 24.6°C | 19.1°C | 13.7°C | 33.2°C | 6.6°C | 129 mm | 75% | 1 m/s | 4.2 |
| 2011 🌧️ | 23.8°C | 19.5°C | 15.3°C | 28.1°C | 5.6°C | 312 mm | 88% | 0.9 m/s | 3.1 |
| 2010 | 27.5°C | 21.1°C | 14.7°C | 36.1°C | 8.6°C | 173 mm | 63% | 1.1 m/s | 4.6 |
| 2009 | 22.5°C | 17.7°C | 13.0°C | 27.3°C | 7.8°C | 108 mm | 80% | 1 m/s | 4 |
| 2008 | 25.4°C | 19.9°C | 14.3°C | 34.1°C | 7.0°C | 161 mm | 74% | 1 m/s | 4.3 |
| 2007 | 27.4°C | 20.9°C | 14.4°C | 32.7°C | 6.8°C | 31 mm | 67% | 0.9 m/s | 5.1 |
| 2006 | 22.6°C | 17.7°C | 12.7°C | 27.5°C | 6.1°C | 140 mm | 81% | 1 m/s | 3.4 |
| 2005 | 28.9°C | 22.1°C | 15.3°C | 33.8°C | 6.5°C | 20 mm | 61% | 0.9 m/s | 4.9 |
| 2004 | 25.2°C | 19.8°C | 14.4°C | 29.1°C | 6.6°C | 189 mm | 81% | 1 m/s | 4 |
| 2003 | 23.8°C | 18.9°C | 14.0°C | 27.9°C | 5.9°C | 203 mm | 83% | 1.1 m/s | 3.7 |
| 2002 | 27.3°C | 20.9°C | 14.5°C | 34.4°C | 8.7°C | 104 mm | 65% | 1 m/s | 4.3 |
| 2001 | 25.2°C | 18.5°C | 11.9°C | 31.0°C | 5.2°C | 89 mm | 65% | 1 m/s | 4.6 |
| 2000 | 23.5°C | 17.5°C | 11.5°C | 30.9°C | 2.6°C | 132 mm | 74% | 1 m/s | 4.2 |
| 1999 | 24.2°C | 18.8°C | 13.4°C | 30.9°C | 5.6°C | 287 mm | 78% | 1.2 m/s | 4 |
| 1998 | 28.0°C | 21.3°C | 14.6°C | 33.8°C | 5.2°C | 53 mm | 63% | 1 m/s | 4.5 |
| 1997 | 24.4°C | 18.4°C | 12.4°C | 31.6°C | 5.1°C | 71 mm | 68% | 1.1 m/s | 4.3 |
| 1996 | 23.9°C | 18.7°C | 13.6°C | 30.0°C | 7.5°C | 135 mm | 80% | 1.1 m/s | 3.7 |
| 1995 | 25.5°C | 19.0°C | 12.5°C | 32.9°C | 5.2°C | 83 mm | 63% | 1 m/s | 4.2 |
| 1994 | 23.6°C | 17.8°C | 12.0°C | 30.2°C | 6.1°C | 83 mm | 73% | 1 m/s | 4.2 |
| 1993 | 24.2°C | 19.0°C | 13.8°C | 32.3°C | 4.7°C | 172 mm | 75% | 1 m/s | 3.4 |
| 1992 | 24.2°C | 18.5°C | 12.8°C | 29.8°C | 3.2°C | 122 mm | 74% | 1.1 m/s | 3.8 |
| 1991 | 25.1°C | 19.0°C | 12.8°C | 34.2°C | 3.1°C | 101 mm | 67% | 0.9 m/s | 4.2 |
| 1990 | 24.4°C | 18.3°C | 12.2°C | 32.2°C | 3.4°C | 56 mm | 72% | 1 m/s | 4.1 |
| 1989 | 24.6°C | 19.1°C | 13.7°C | 33.3°C | 4.1°C | 107 mm | 76% | 1 m/s | 3.8 |
| 1988 | 24.0°C | 17.8°C | 11.6°C | 29.4°C | 6.5°C | 74 mm | 72% | 0.9 m/s | 4.2 |
| 1987 | 23.7°C | 18.6°C | 13.6°C | 27.3°C | 6.9°C | 203 mm | 80% | 0.9 m/s | 3.8 |
| 1986 | 25.4°C | 19.3°C | 13.3°C | 32.0°C | 4.3°C | 45 mm | 71% | 1 m/s | 3.8 |
| 1985 | 26.5°C | 20.1°C | 13.7°C | 34.2°C | 6.2°C | 145 mm | 65% | 0.9 m/s | 4.4 |
| 1984 ❄️ | 23.7°C | 17.3°C | 10.9°C | 30.4°C | 4.5°C | 47 mm | 71% | 1 m/s | 4.6 |
| 1983 | 27.3°C | 20.2°C | 13.1°C | 36.1°C | 4.5°C | 50 mm | 58% | 1 m/s | — |
| 1982 | 25.6°C | 19.4°C | 13.2°C | 31.3°C | 8.2°C | 78 mm | 68% | 0.9 m/s | — |
| 1981 | 24.6°C | 18.6°C | 12.5°C | 32.4°C | 4.6°C | 79 mm | 68% | 1 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 25.4°C with lows near 13.7°C (mean 19.5°C), based on 45 years of NASA POWER data.
September averages 112 mm of rainfall in Lancaster, a relatively wet time of year. The wettest on record was 312 mm in 2011.
The hottest September reached 36.9°C in 2023. The coldest dipped to 2.6°C in 2000.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.4°C. Daytime highs moved from 25.5°C to 26.2°C and overnight lows from 12.7°C to 14.8°C over the same span.
September is one of the warmer months of the year in Lancaster and a relatively wet time of year, so plan for around 25.4°C daytime highs and 13.7°C at night.
Not quite — September is the 9th coolest month in Lancaster, averaging 19.5°C.
For September in Lancaster, pack light layers you can adjust through the day, with typical highs of 25.4°C and lows of 13.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 72% — moderately humid.
Average wind speed in September is 1 m/s. The windiest September on record averaged 1.2 m/s (1999).
The wettest September on record was 2011 with 312 mm. On average, September sees 112 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.
