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September Weather in Pomona, United States

Last updated: June 24, 2025

In September, the average temperature in Pomona, United States is a comfortable 23°C (73°F). However, be prepared for a range of temperatures, as it can dip as low as 7°C (45°F) or soar up to 35°C (95°F). Expect some rainfall too, with an average precipitation of 50 mm (2.0 in) spread over 6 days. With an average humidity of 68%, you'll want to dress accordingly for both warmth and moisture!

September Temperature in Pomona

In September in Pomona, the average temperature is 23°C (73°F), with maximums reaching 35°C (95°F) and minimums dipping as low as 7°C (45°F). It's advisable to pack both light clothing for the warmth and warmer layers for the cooler evenings during your travels.

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

The chart illustrates September temperature patterns in Pomona, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Pomona, September typically has an average temperature of 23°C (73°F), with highs reaching up to 35°C (95°F) and lows dropping to around 7°C (45°F).
JanFebMarAprMayJunJulAugSepOctNovDec363950566675797773594642
Data source: Temperature data for Pomona 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 Pomona

In Pomona in September, the precipitation amount is 50 mm (2.0 in) over the course of 6 days.

September Precipitation Trends in Pomona

The chart displays monthly precipitation patterns in Pomona, 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 Pomona, September typically receives around 50 mm (2.0 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec841131531631877977109501277677
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Pomona

In Pomona in September humidity is 68%. With an average temperature of 23°C (73°F), this humidity feels like a soft blanket wrapping around you, making every step outside feel a bit heavier, but offering a warm embrace that encourages leisurely exploration and a relaxed pace for travel.

September Average Humidity in Pomona

This chart illustrates the average monthly humidity levels in Pomona, 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 Pomona is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec83%81%80%80%83%83%76%69%68%72%83%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Pomona

In Pomona 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 Pomona.

Maximum UV Index Levels in Pomona for September

The chart shows the monthly maximum UV Index (UVI) for Pomona 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 Pomona typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710111111109753
Data source: Pomona 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 Pomona Compares to Other Months

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

This table compares monthly weather conditions in Pomona, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather2°C (36°F)84 mm (3.3 inches)83%moderate
February Weather4°C (39°F)113 mm (4.4 inches)81%high
March Weather10°C (50°F)153 mm (6.0 inches)80%high
April Weather13°C (56°F)163 mm (6.4 inches)80%very high
May Weather19°C (67°F)187 mm (7.4 inches)83%extreme
June Weather24°C (75°F)79 mm (3.1 inches)83%extreme
July Weather26°C (79°F)77 mm (3.0 inches)76%extreme
August Weather25°C (77°F)109 mm (4.3 inches)69%very high
September Weather23°C (73°F)50 mm (2.0 inches)68%very high
October Weather15°C (60°F)127 mm (5.0 inches)72%high
November Weather8°C (46°F)76 mm (3.0 inches)83%moderate
December Weather5°C (42°F)77 mm (3.0 inches)86%moderate

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