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September Weather in Union City, United States

Last updated: June 24, 2025

In Union City, United States, the average temperature in September reaches a mild 24°C (76°F). Temperatures can swing from a cool 7°C (45°F) at their lowest to a sizzling 38°C (101°F) at their peak. Expect 80 mm (3.2 in) of precipitation over approximately 5 days, accompanied by an average humidity of 64%. Enjoy the varying climate while planning your visit!

September Temperature in Union City

In September in Union City, the average temperature is 24°C (76°F). Maximum temperatures can reach 38°C (101°F), while minimum temperatures can drop as low as 7°C (45°F). Travelers should prepare for warm days and cooler nights, making layering essential for comfort.

September Weather in Union City: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Union City, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Union City, September typically has an average temperature of 24°C (76°F), with highs reaching up to 38°C (101°F) and lows dropping to around 7°C (45°F).
JanFebMarAprMayJunJulAugSepOctNovDec394053596979838175614943
Data source: Temperature data for Union City 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 Union City

In Union City in September, the precipitation amount is 80 mm (3.2 in) over a span of 5 days.

September Precipitation Trends in Union City

The chart displays monthly precipitation patterns in Union City, 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 Union City, September typically receives around 80 mm (3.2 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec41387810114088535880942733
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Union City

In Union City in September, humidity is 64%. With an average temperature of 24°C (76°F), this humidity feels like a warm, sticky embrace, making travel slightly uncomfortable but still enjoyable, as you may find yourself yearning for a refreshing breeze or a quick dip in the water.

September Average Humidity in Union City

This chart illustrates the average monthly humidity levels in Union City, 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 Union City is approximately 64%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%76%70%72%82%82%80%72%64%71%81%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Union City

In Union City 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 Union City.

Maximum UV Index Levels in Union City for September

The chart shows the monthly maximum UV Index (UVI) for Union City 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 Union City typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101111121110753
Data source: Union City 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 Union City Compares to Other Months

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

This table compares monthly weather conditions in Union City, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (39°F)41 mm (1.6 inches)76%moderate
February Weather4°C (40°F)38 mm (1.5 inches)76%high
March Weather12°C (53°F)78 mm (3.1 inches)70%very high
April Weather15°C (59°F)101 mm (4.0 inches)72%very high
May Weather21°C (70°F)140 mm (5.5 inches)82%extreme
June Weather26°C (79°F)88 mm (3.5 inches)82%extreme
July Weather28°C (83°F)53 mm (2.1 inches)80%extreme
August Weather27°C (81°F)58 mm (2.3 inches)72%extreme
September Weather24°C (76°F)80 mm (3.2 inches)64%very high
October Weather16°C (62°F)94 mm (3.7 inches)71%high
November Weather10°C (50°F)27 mm (1.1 inches)81%moderate
December Weather6°C (44°F)33 mm (1.3 inches)84%moderate

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