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December Weather in South Bay, United States

Last updated: June 24, 2025

In South Bay, United States, the average temperature in December hovers around 20°C (69°F), providing a comfortable climate. Expect minimum temperatures dipping to 8°C (47°F), while highs can reach up to 28°C (83°F). During this month, anticipate approximately 40 mm (1.6 in) of precipitation over a span of 6 days, contributing to an average humidity level of 84%.

December Temperature in South Bay

In December in South Bay, the average temperature is 20°C (69°F). Maximum temperatures can reach 28°C (83°F), while minimum temperatures can be as low as 8°C (47°F). This mild climate makes South Bay an ideal destination for travelers seeking comfortable weather and a variety of outdoor activities.

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

The chart illustrates December 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, December typically has an average temperature of 20°C (69°F), with highs reaching up to 28°C (83°F) and lows dropping to around 8°C (47°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.

December Precipitation in South Bay

In South Bay in December, the precipitation amount is 40 mm (1.6 in) over the course of 6 days.

December Precipitation Trends in South Bay

The chart displays monthly precipitation patterns in South Bay, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In South Bay, December typically receives around 40 mm (1.6 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec394026531381921662001611234940
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in South Bay

In South Bay in December humidity is 84%. With an average temperature of 20°C (69°F), this humidity feels like walking through a warm, moist blanket, making travel feel heavy and slightly fatigued as the heat clings to your skin and leaves you yearning for a refreshing breeze.

December Average Humidity in South Bay

This chart illustrates the average monthly humidity levels in South Bay, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in South Bay is approximately 84%, 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 December generated using information from the Copernicus Climate Change Service.

December UV Index in South Bay

In South Bay in December, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in South Bay.

Maximum UV Index Levels in South Bay for December

The chart shows the monthly maximum UV Index (UVI) for South Bay in December, 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 December, the maximum UV index in South Bay typically reaches 5, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec69101211121212111075
Data source: South Bay December 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 December 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 December’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 December’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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