December Weather in Merced, United States

Last updated: June 24, 2025

In December, the average temperature in Merced, United States hovers around 10°C (50°F), with a minimum of -2°C (28°F) and a pleasant maximum of 23°C (73°F). Expect about 83 mm (3.3 in) of precipitation spread over 8 days, and enjoy a relatively high average humidity of 80%.

December Temperature in Merced

In December in Merced, the average temperature is 10°C (50°F). Maximums can reach 23°C (73°F), while minimums can drop to as low as -2°C (28°F). This varied climate makes it essential for travelers to pack layers to adjust to shifting temperatures throughout the day.

December Weather in Merced: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Merced, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Merced, December typically has an average temperature of 10°C (50°F), with highs reaching up to 23°C (73°F) and lows dropping to around -2°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec505357657280868478675750
Data source: Temperature data for Merced 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 Merced

In Merced in December, the precipitation amount reaches 83 mm (3.3 in) over the course of 8 days.

December Precipitation Trends in Merced

The chart displays monthly precipitation patterns in Merced, 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 Merced, December typically receives around 83 mm (3.3 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec96738928231000173183
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Merced

In Merced in December, humidity is 80%. With an average temperature of 10°C (50°F), this humidity feels like a damp chill enveloping you, making traveling somewhat uncomfortable as it seeps into your clothes and clings to your skin, leaving you longing for a cozy indoor refuge.

December Average Humidity in Merced

This chart illustrates the average monthly humidity levels in Merced, 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 Merced is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%84%82%78%71%64%59%54%55%62%78%80%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Merced

In Merced in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Merced, you can check the information here.

Maximum UV Index Levels in Merced for December

The chart shows the monthly maximum UV Index (UVI) for Merced 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 Merced typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3589101111109743
Data source: Merced 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 Merced Compares to Other Months

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

This table compares monthly weather conditions in Merced, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather10°C (51°F)96 mm (3.8 inches)82%moderate
February Weather12°C (53°F)73 mm (2.9 inches)84%moderate
March Weather14°C (57°F)89 mm (3.5 inches)82%very high
April Weather18°C (65°F)28 mm (1.1 inches)78%very high
May Weather22°C (72°F)23 mm (0.9 inches)71%very high
June Weather27°C (81°F)1 mm (0.0 inches)64%extreme
July Weather30°C (86°F)0 mm (0.0 inches)58%extreme
August Weather29°C (84°F)0 mm (0.0 inches)54%very high
September Weather26°C (78°F)0 mm (0.0 inches)55%very high
October Weather19°C (67°F)17 mm (0.7 inches)62%high
November Weather14°C (57°F)31 mm (1.2 inches)78%moderate
December Weather10°C (50°F)83 mm (3.3 inches)80%moderate

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