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September Weather in Downey, United States

Last updated: June 24, 2025

The average temperature in Downey, United States during September is a comfortable 15°C (60°F). Expect a minimum dip to -1°C (30°F) and a maximum rise up to 34°C (93°F). During this month, Downey sees around 35 mm (1.4 in) of precipitation over approximately 5 days, accompanied by an average humidity of 52%.

September Temperature in Downey

In September in Downey, the average temperature is 15°C (60°F). The maximum can reach 34°C (93°F), while the minimum can drop as low as -1°C (30°F). This diverse temperature range makes Downey an interesting destination for travelers, offering the opportunity to enjoy both warm and cool weather experiences.

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

The chart illustrates September temperature patterns in Downey, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Downey, September typically has an average temperature of 15°C (60°F), with highs reaching up to 34°C (93°F) and lows dropping to around -1°C (30°F).
JanFebMarAprMayJunJulAugSepOctNovDec222433415163727060433322
Data source: Temperature data for Downey 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 Downey

In Downey in September, the precipitation amount is 35 mm (1.4 in) over a span of 5 days.

September Precipitation Trends in Downey

The chart displays monthly precipitation patterns in Downey, 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 Downey, September typically receives around 35 mm (1.4 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec597850696129142235454654
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Downey

In Downey in September, humidity is 52%. With an average temperature of 15°C (60°F), this humidity feels like a refreshing embrace for traveling, making outdoor exploration enjoyable without feeling overly sticky or uncomfortable.

September Average Humidity in Downey

This chart illustrates the average monthly humidity levels in Downey, 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 Downey is approximately 52%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec95%95%90%81%71%64%59%49%52%69%86%91%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Downey

In Downey in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Downey.

Maximum UV Index Levels in Downey for September

The chart shows the monthly maximum UV Index (UVI) for Downey 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 Downey typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3589101111109643
Data source: Downey 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 Downey Compares to Other Months

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

This table compares monthly weather conditions in Downey, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (22°F)59 mm (2.3 inches)95%moderate
February Weather-4°C (25°F)78 mm (3.1 inches)95%moderate
March Weather1°C (33°F)50 mm (2.0 inches)90%very high
April Weather5°C (41°F)69 mm (2.7 inches)81%very high
May Weather11°C (51°F)60 mm (2.4 inches)71%very high
June Weather17°C (63°F)29 mm (1.1 inches)64%extreme
July Weather22°C (72°F)14 mm (0.6 inches)59%extreme
August Weather21°C (70°F)22 mm (0.9 inches)49%very high
September Weather15°C (60°F)35 mm (1.4 inches)52%very high
October Weather6°C (44°F)45 mm (1.8 inches)69%high
November Weather1°C (33°F)46 mm (1.8 inches)86%moderate
December Weather-5°C (23°F)54 mm (2.1 inches)91%moderate

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