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September Weather in South Bay, United States

Last updated: June 24, 2025

In South Bay, United States, the average temperature in September hovers around 27°C (82°F), with a comfortable range from a minimum of 23°C (73°F) to a maximum of 32°C (91°F). However, be prepared for the wet season, as you'll likely encounter about 161 mm (6.3 in) of precipitation over 21 days. Don't forget to stay hydrated; the average humidity is a notable 83%!

September Temperature in South Bay

In September, in South Bay, the average temperature is 27°C (82°F), with maximums reaching 32°C (91°F) and minimums dropping to as low as 23°C (73°F). This mild climate makes South Bay an ideal destination for travelers seeking warmth and pleasant weather.

September Weather in South Bay: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in South Bay, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In South Bay, September typically has an average temperature of 27°C (82°F), with highs reaching up to 32°C (91°F) and lows dropping to around 23°C (73°F).
JanFebMarAprMayJunJulAugSepOctNovDec667172767981828281797369
Data source: Temperature data for South Bay 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 South Bay

In South Bay in September, the total precipitation amount is 161 mm (6.3 in) distributed over 21 days.

September Precipitation Trends in South Bay

The chart displays monthly precipitation patterns in South Bay, 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 South Bay, September typically receives around 161 mm (6.3 inches) of precipitation spread over approximately 21 days.
JanFebMarAprMayJunJulAugSepOctNovDec394026531381921662001611234940
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in South Bay

In South Bay in September humidity is 83%. With an average temperature of 27°C (82°F), this humidity feels like a thick, warm blanket enveloping you, making outdoor activities exhausting and encouraging visitors to seek the comfort of shade or air conditioning while exploring the area.

September Average Humidity in South Bay

This chart illustrates the average monthly humidity levels in South Bay, 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 South Bay is approximately 83%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec83%80%75%68%65%73%77%80%83%83%83%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in South Bay

In South Bay in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in South Bay.

Maximum UV Index Levels in South Bay for September

The chart shows the monthly maximum UV Index (UVI) for South Bay 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 South Bay typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec69101211121212111075
Data source: South Bay 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 South Bay Compares to Other Months

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

This table compares monthly weather conditions in South Bay, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather19°C (67°F)39 mm (1.5 inches)83%high
February Weather21°C (71°F)40 mm (1.6 inches)80%very high
March Weather22°C (72°F)26 mm (1.0 inches)75%very high
April Weather25°C (76°F)53 mm (2.1 inches)68%extreme
May Weather26°C (79°F)138 mm (5.4 inches)65%extreme
June Weather27°C (81°F)192 mm (7.6 inches)73%extreme
July Weather28°C (82°F)166 mm (6.5 inches)77%extreme
August Weather28°C (82°F)200 mm (7.9 inches)80%extreme
September Weather27°C (82°F)161 mm (6.3 inches)83%extreme
October Weather26°C (80°F)123 mm (4.8 inches)83%very high
November Weather23°C (74°F)49 mm (1.9 inches)83%high
December Weather20°C (69°F)40 mm (1.6 inches)84%moderate

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