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September Weather in El Cajon, United States

Last updated: June 24, 2025

In September, the average temperature in El Cajon, United States is a pleasant 22°C (72°F). Expect a range from a cool 14°C (57°F) to a warm 38°C (101°F). During this month, precipitation is minimal at 4 mm (0.1 in) over just 1 day, and the average humidity hovers around 52%.

September Temperature in El Cajon

In September in El Cajon, the average temperature is 22°C (72°F), with maximums reaching 38°C (101°F) and minimums dipping as low as 14°C (57°F). This comfortable climate makes El Cajon an ideal destination for travelers looking to enjoy a pleasant getaway.

September Weather in El Cajon: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in El Cajon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In El Cajon, September typically has an average temperature of 22°C (72°F), with highs reaching up to 38°C (101°F) and lows dropping to around 14°C (57°F).
JanFebMarAprMayJunJulAugSepOctNovDec565557616367727372686256
Data source: Temperature data for El Cajon 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 El Cajon

In El Cajon in September, the precipitation amount is 4 mm (0.1 in) over the course of 1 day.

September Precipitation Trends in El Cajon

The chart displays monthly precipitation patterns in El Cajon, 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 El Cajon, September typically receives around 4 mm (0.1 inches) of precipitation spread over approximately 1 days.
JanFebMarAprMayJunJulAugSepOctNovDec56685124222314142965
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in El Cajon

In El Cajon in September humidity is 52%. With an average temperature of 22°C (72°F), this humidity feels like a refreshing embrace during your travels, creating a pleasant sensation that makes outdoor activities enjoyable and inviting.

September Average Humidity in El Cajon

This chart illustrates the average monthly humidity levels in El Cajon, 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 El Cajon is approximately 52%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec72%77%67%56%46%48%46%42%52%58%66%74%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in El Cajon

In El Cajon in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in El Cajon.

Maximum UV Index Levels in El Cajon for September

The chart shows the monthly maximum UV Index (UVI) for El Cajon 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 El Cajon typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101111111010754
Data source: El Cajon 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 El Cajon Compares to Other Months

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

This table compares monthly weather conditions in El Cajon, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather13°C (56°F)56 mm (2.2 inches)72%moderate
February Weather13°C (56°F)68 mm (2.7 inches)77%high
March Weather14°C (57°F)51 mm (2.0 inches)67%very high
April Weather16°C (61°F)24 mm (0.9 inches)56%very high
May Weather17°C (63°F)21 mm (0.8 inches)46%extreme
June Weather19°C (67°F)2 mm (0.1 inches)48%extreme
July Weather22°C (72°F)3 mm (0.1 inches)46%extreme
August Weather23°C (74°F)1 mm (0.1 inches)42%very high
September Weather22°C (72°F)4 mm (0.1 inches)52%very high
October Weather20°C (68°F)14 mm (0.6 inches)58%high
November Weather17°C (62°F)29 mm (1.1 inches)66%moderate
December Weather14°C (57°F)65 mm (2.5 inches)74%moderate

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