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September Weather in Lancaster, United States

Last updated: June 24, 2025

In September, the average temperature in Lancaster, United States is a pleasant 21°C (70°F). Expect a minimum of around 6°C (43°F), while highs can reach up to 34°C (93°F). During this month, precipitation averages 116 mm (4.6 in) over about 8 days, contributing to an average humidity level of 73%.

September Temperature in Lancaster

In September in Lancaster, the average temperature is 21°C (70°F), with maximums reaching 34°C (93°F) and minimums dropping as low as 6°C (43°F). This makes it a great time to explore the area, as you can enjoy warm days and cool evenings.

September Weather in Lancaster: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Lancaster, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Lancaster, September typically has an average temperature of 21°C (70°F), with highs reaching up to 34°C (93°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec262842516475787569544034
Data source: Temperature data for Lancaster generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Lancaster

In Lancaster in September, the total precipitation amount is 116 mm (4.6 in) recorded over a span of 8 days.

September Precipitation Trends in Lancaster

The chart displays monthly precipitation patterns in Lancaster, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Lancaster, September typically receives around 116 mm (4.6 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec5453988415212082751161265036
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Lancaster

In Lancaster in September, humidity is 73%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace that can make outdoor activities feel sweltering, so it's essential to stay hydrated and take breaks in the shade while exploring.

September Average Humidity in Lancaster

This chart illustrates the average monthly humidity levels in Lancaster, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Lancaster is approximately 73%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec78%80%77%78%77%81%81%77%73%75%85%83%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Lancaster

In Lancaster in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Lancaster.

Maximum UV Index Levels in Lancaster for September

The chart shows the monthly maximum UV Index (UVI) for Lancaster in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Lancaster typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3569101111108642
Data source: Lancaster September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in Lancaster Compares to Other Months

Weather in Lancaster varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Lancaster, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Lancaster, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (26°F)54 mm (2.1 inches)78%moderate
February Weather-2°C (29°F)53 mm (2.1 inches)80%moderate
March Weather6°C (42°F)98 mm (3.9 inches)77%high
April Weather10°C (51°F)84 mm (3.3 inches)77%very high
May Weather18°C (64°F)152 mm (6.0 inches)77%very high
June Weather24°C (75°F)120 mm (4.7 inches)81%extreme
July Weather26°C (79°F)82 mm (3.2 inches)81%extreme
August Weather24°C (75°F)75 mm (2.9 inches)77%very high
September Weather21°C (70°F)116 mm (4.6 inches)73%very high
October Weather12°C (55°F)126 mm (5.0 inches)75%high
November Weather5°C (41°F)50 mm (2.0 inches)85%moderate
December Weather1°C (34°F)36 mm (1.4 inches)83%low

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