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September Weather in Crestline, United States

Last updated: June 24, 2025

In September, the average temperature in Crestline, United States hovers around 20°C (67°F). Expect lows of 4°C (40°F) and highs reaching 33°C (92°F). With an average humidity of 78%, the weather can feel quite warm and muggy. Be prepared for some rain, as 79 mm (3.1 in) of precipitation is expected over 9 days.

September Temperature in Crestline

In September in Crestline, the average temperature is 20°C (67°F). The maximum can reach 33°C (92°F), and the minimum can be as low as 4°C (40°F). It's an ideal time for travelers to enjoy mild weather and explore both outdoor activities and cultural sites.

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

The chart illustrates September temperature patterns in Crestline, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Crestline, September typically has an average temperature of 20°C (67°F), with highs reaching up to 33°C (92°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec293240506270747267564134
Data source: Temperature data for Crestline 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 Crestline

In Crestline in September, the precipitation amount is 79 mm (3.1 in) spread over 9 days.

September Precipitation Trends in Crestline

The chart displays monthly precipitation patterns in Crestline, 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 Crestline, September typically receives around 79 mm (3.1 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec821021031261291461248179999691
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Crestline

In Crestline in September humidity is 78%. With an average temperature of 20°C (67°F), this humidity feels like walking through a warm, thick blanket, making travel a bit sticky and requiring frequent breaks to find shade and cool refreshments.

September Average Humidity in Crestline

This chart illustrates the average monthly humidity levels in Crestline, 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 Crestline is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%87%87%88%81%82%81%78%78%82%89%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Crestline

In Crestline 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 Crestline.

Maximum UV Index Levels in Crestline for September

The chart shows the monthly maximum UV Index (UVI) for Crestline 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 Crestline typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
Data source: Crestline 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 Crestline Compares to Other Months

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

This table compares monthly weather conditions in Crestline, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)82 mm (3.2 inches)88%moderate
February Weather0°C (32°F)102 mm (4.0 inches)87%moderate
March Weather5°C (40°F)103 mm (4.1 inches)87%high
April Weather10°C (50°F)126 mm (5.0 inches)87%very high
May Weather17°C (62°F)129 mm (5.1 inches)81%very high
June Weather21°C (71°F)146 mm (5.7 inches)82%very high
July Weather23°C (74°F)124 mm (4.9 inches)81%very high
August Weather22°C (72°F)81 mm (3.2 inches)78%very high
September Weather20°C (67°F)79 mm (3.1 inches)78%very high
October Weather14°C (57°F)98 mm (3.9 inches)82%high
November Weather5°C (41°F)96 mm (3.8 inches)89%moderate
December Weather1°C (35°F)91 mm (3.6 inches)86%low

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