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September Weather in Pomona, United States

Last updated: June 24, 2025

In September, the average temperature in Pomona, United States hovers around 22°C (72°F), offering a pleasant climate for outdoor activities. Expect a minimum of 5°C (41°F) and a potential maximum of 34°C (94°F), showcasing a broad temperature range. During this time, anticipate about 80 mm (3.1 in) of precipitation over 7 days, contributing to an average humidity of 71%. Be prepared for a mix of sun and occasional rain!

September Temperature in Pomona

In September in Pomona, the average temperature is 22°C (72°F). The maximum can reach 34°C (94°F), and the minimum can be as low as 5°C (41°F). This makes it an ideal time for travelers to experience a range of weather conditions, so packing accordingly is essential.

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 22°C (72°F), with highs reaching up to 34°C (94°F) and lows dropping to around 5°C (41°F).
JanFebMarAprMayJunJulAugSepOctNovDec323447556677807772574539
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 80 mm (3.1 in) during a span of 7 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 80 mm (3.1 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec53359594202111105121801183832
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 71%. With an average temperature of 22°C (72°F), this humidity feels like the air is thick and slightly stifling, making outdoor activities require frequent breaks to stay hydrated and cool.

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 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%78%70%73%82%82%81%78%71%71%81%84%
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.
JanFebMarAprMayJunJulAugSepOctNovDec3679101111109743
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 Weather0°C (33°F)53 mm (2.1 inches)76%moderate
February Weather1°C (34°F)35 mm (1.4 inches)77%high
March Weather9°C (48°F)95 mm (3.7 inches)70%high
April Weather13°C (55°F)94 mm (3.7 inches)73%very high
May Weather19°C (66°F)202 mm (7.9 inches)82%very high
June Weather25°C (78°F)111 mm (4.4 inches)82%extreme
July Weather27°C (80°F)105 mm (4.1 inches)81%extreme
August Weather25°C (77°F)121 mm (4.8 inches)78%very high
September Weather22°C (72°F)80 mm (3.1 inches)71%very high
October Weather14°C (58°F)118 mm (4.6 inches)71%high
November Weather7°C (45°F)38 mm (1.5 inches)81%moderate
December Weather4°C (39°F)32 mm (1.3 inches)84%moderate

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