December Weather in Mendocino, United States

Last updated: February 24, 2025

In Mendocino, United States, December brings a blend of cool temperatures and ample moisture, creating a unique winter atmosphere. With maximum temperatures reaching 20°C (68°F) and dipping to a chilly 2°C (35°F) at night, the average daily temperature hovers around 10°C (50°F). During this month, residents and visitors can expect 97 mm (3.8 in) of precipitation spread over approximately 11 days, contributing to the region's lush landscapes. The high humidity level of 84% adds to the crisp coastal charm, making December an evocative time to experience Mendocino's natural beauty.

December Temperature in Mendocino

In Mendocino, United States, December welcomes the winter season with a mild chill, showcasing minimum temperatures around 2°C (35°F) and maximums reaching 20°C (68°F). The average temperature remains stable at 10°C (50°F), reflecting a gradual dip from the warmer autumn months. This trend underscores a consistent climate pattern as the year winds down, with temperatures slightly cooler than November, yet still comfortable compared to the stark cold found in many regions. As the coastal town embraces the beauty of winter, residents and visitors can enjoy refreshing seaside strolls in a serene and temperate atmosphere.

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

The chart illustrates December temperature patterns in Mendocino, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec505051545661636464595350
Data source: Temperature data for Mendocino 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 Mendocino

In December, Mendocino experiences a notable increase in precipitation, with 97 mm (3.8 in) falling over 11 rainy days. This marked wetness contributes to the overall trend of winter months being significantly wetter than the drier summer season, where rainfall plummets to negligible levels. As the year comes to a close, December's precipitation levels rise from the previous month’s 72 mm (2.8 in), reflecting the region’s characteristic seasonal shift. This pattern not only highlights Mendocino's robust winter rainfall but also sets the stage for the lush landscapes that flourish in the months to come.

December Precipitation Trends in Mendocino

The chart displays monthly precipitation patterns in Mendocino, 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.
JanFebMarAprMayJunJulAugSepOctNovDec14813710860432216437297
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Mendocino

As December settles in Mendocino, the air carries a familiar humidity of 84%, mirroring the levels of both November and the winter months preceding it. This seasonal consistency is part of a broader trend where humidity remains elevated during the colder half of the year, peaking in January, and then gradually declining towards the summer. From a high of 86% in January to lows around 66% in August, the region experiences a noteworthy seasonal ebb and flow. Each month contributes to the maritime influence that shapes Mendocino’s climate, creating a distinctly refreshing atmosphere as the year draws to a close.

December Average Humidity in Mendocino

This chart illustrates the average monthly humidity levels in Mendocino, with December's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how December's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%83%80%80%76%70%66%68%72%84%84%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Mendocino

In Mendocino, the UV Index trends throughout the year showcase a remarkable seasonal variation. As the year winds down to December, the UV Index drops to a moderate 3, which means you have a burn time of 30 minutes before needing protection. This decline in UV radiation is a stark contrast to the summer months, particularly May through July, where the index reaches an extreme high of 11, demanding vigilance with a burn time of just 10 minutes. Spring introduces a gradual increase, with March peaking at 7 and April escalating to 8. As we transition towards the cooler months, November sees a slight dip to 4, further followed by December's pleasant reprieve. For more detailed insights on UV exposure in the area, check out Mendocino UV Index.

Maximum UV Index Levels in Mendocino for December

The chart shows the monthly maximum UV Index (UVI) for Mendocino 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.
JanFebMarAprMayJunJulAugSepOctNovDec3578111111108643
Data source: Mendocino 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.

December Sunshine in Mendocino

As December envelops Mendocino in a gentle embrace, the region experiences a notable shift in sunshine hours, with an average of 175 hours this month. While this marks a dip from the vibrant late autumn, the sunlight still lingers, embracing the coastal beauty. Interestingly, the year begins with a modest 133 hours in January, gradually building to a luminous peak in the summer months, where July shines brightest at 386 hours. This trend highlights Mendocino's seasonal rhythm, transitioning from crisp winter days to sun-drenched summer afternoons, offering locals and visitors alike a diverse experience of California's stunning coastal landscape.

Monthly Sunshine Duration in Mendocino: December Highlighted

The December sunshine duration represents the total number of hours Mendocino experiences direct sunlight during the month of December, excluding cloudy or obstructed periods. This chart compares the sunshine duration of December with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec133h205h261h290h348h376h386h344h302h275h208h175h
Data source: Mendocino December Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Mendocino During December

In December, Mendocino experiences a notable dip in the likelihood of sunny weather, with the chance of sunshine dropping to 32%. This trend marks a significant decline from the sunnier months of late spring and early summer, where the probability peaks at 70% in May. As the year progresses towards winter, the gradual decrease in sunshine is apparent; for instance, the chances fall from 40% in November to December's 32%. This seasonal shift highlights Mendocino's tendency towards cloudier and wetter conditions as the region embraces the winter months, making the rare sunlit days even more cherished for residents and visitors alike.

Percentage of Sunny Days in December in Mendocino

The chart illustrates the percentage of sunny days in Mendocino throughout the year, with December highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Mendocino experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec35%52%58%60%70%56%52%63%57%46%40%32%
Data source: Mendocino December chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Mendocino in December

In Mendocino, the rhythm of daylight duration dances through the seasons, with December marking a notable shift as it returns to 9 hours of daylight, mirroring the earlier months of January and November. This brief daylight period heralds the onset of winter, following the gradual increase in light from a mere 9 hours in January to a peak of 14 hours in both May and June. As autumn progresses, the hours of daylight wane, tapering down to 12 hours in September and descending once more to 11 hours in October. The trend reveals a gentle ebb and flow, with Mendocino basking in longer days during spring and summer, while the onset of winter brings a cozy return to shorter daylight hours, creating a picturesque seasonal cycle.

Average Daylight Hours in Mendocino for December

The chart illustrates the variation in daylight duration in Mendocino throughout the year, with December highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 44m10h 43m11h 58m13h 15m14h 20m14h 52m14h 34m13h 37m12h 23m11h 6m9h 59m9h 26m
Data source: Mendocino daylight hours, calculated by summing the hours between sunrise and sunset for each day.

December Winds in Mendocino

As December rolls into Mendocino, the coastal breezes continue to dance gently, with an average wind speed of 3.2 m/s (7 mph). While this month sees a slight dip compared to the more blustery late spring of May, characterized by gusts reaching up to 5.0 m/s (11 mph), it still carries a refreshing chill that’s emblematic of winter at the coast. Notably, the trend shows a gradual decrease in wind speeds from the vibrant energies of spring through to the calmer, gentler winds of late fall and winter. The winds of December, while subdued, evoke a sense of tranquility, inviting locals and visitors alike to embrace the serene beauty of this coastal haven as the year winds down.

Average December Wind Speed in Mendocino

The chart displays monthly wind speed patterns in Mendocino, with values for each month shown alongside December's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how December's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.33.93.73.55.03.73.33.12.73.52.53.2 m/s
Data source: Mendocino December wind data, generated using information from the Copernicus Climate Change Service.

How December Weather in Mendocino Compares to Other Months

The weather in Mendocino changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of December's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Mendocino and find detailed weather information for every month.

In comparison to December, January sees a slight decrease in minimum temperatures, with lows averaging around 1°C (34°F) as opposed to December's 2°C (35°F). While the average temperature remains consistent at 10°C (50°F), January enjoys a marginally warmer maximum at 21°C (69°F) compared to December's 20°C (68°F). Precipitation increases significantly in January, rising to 147 mm (5.8 in) over the same number of rainy days as December, which recorded 97 mm (3.8 in) of rainfall. Furthermore, humidity levels also see a slight uptick, from 84% in December to 86% in January. For more detailed information on January weather, check Mendocino weather in January.

When comparing the weather in December and February, both months exhibit similar average temperatures around 10°C (50°F). However, February tends to be slightly cooler at night with a minimum temperature of 0°C (32°F), while December's minimum typically stays at 2°C (35°F). Interestingly, February also showcases a wider temperature range, with a maximum reaching 24°C (76°F) compared to December's 20°C (68°F). Precipitation levels are notably higher in February, with 137 mm (5.4 in) compared to December's 97 mm (3.8 in), although both months experience precipitation on approximately 11 days. Humidity remains constant at 84% for both months, creating a humid atmosphere throughout this winter season. For more detailed information, check out Mendocino weather in February.

December and March in Mendocino exhibit similar temperature ranges, with both months having a minimum of 2°C (35°F) and an average temperature around 10°C (50°F). However, March tends to be slightly warmer, peaking at a maximum of 23°C (74°F), compared to December's maximum of 20°C (68°F). Precipitation is more pronounced in March, with 108 mm (4.2 in) falling over 13 days, compared to December's 97 mm (3.8 in) over 11 days. Additionally, humidity remains relatively high in both months, with December at 84% and March at 83%. For more detailed information, you can check Mendocino weather in March.

In December, the weather tends to be cooler with an average temperature of 10°C (50°F), ranging from a minimum of 2°C (35°F) to a maximum of 20°C (68°F). This month also experiences higher precipitation, averaging 97 mm (3.8 in) over approximately 11 days, coupled with relatively high humidity levels at 84%. In contrast, April brings slightly warmer conditions, with an average temperature of 12°C (54°F) and a maximum of 23°C (74°F). Precipitation decreases to 60 mm (2.4 in) over about 7 days, and humidity is slightly lower at 80%. For more detailed April weather information, you can check Mendocino weather in April.

December and May present contrasting weather conditions. In December, temperatures range from a minimum of 2°C (35°F) to a maximum of 20°C (68°F), with an average of 10°C (50°F). This month typically experiences 97 mm (3.8 in) of precipitation over 11 days, resulting in a humid environment with an average humidity of 84%. In contrast, May enjoys milder temperatures, with a minimum of 6°C (42°F), an average of 14°C (57°F), and a maximum of 26°C (79°F). The precipitation in May is significantly lower at 43 mm (1.7 in) over just 4 days, and the humidity is slightly reduced at 80%. For more details on May weather, you can explore Mendocino weather in May.

The weather in December contrasts significantly with that of June. In December, temperatures range from a chilly minimum of 2°C (35°F) to a milder maximum of 20°C (68°F), with an average of 10°C (50°F). This month also sees considerable precipitation, totaling 97 mm (3.8 in) over 11 days, contributing to a high humidity level of 84%. In stark contrast, June enjoys warmer temperatures, with a minimum of 9°C (48°F), an average of 16°C (62°F), and a peak of 31°C (88°F). The month is marked by significantly reduced rainfall of just 2 mm (0.1 in) and boasts completely dry conditions, resulting in a lower humidity of 76%. For a more detailed look at the weather in June, check out Mendocino weather in June.

December and July present strikingly different weather conditions. In December, temperatures range from a chilly minimum of 2°C (35°F) to a comfortable average of 10°C (50°F), peaking at 20°C (68°F). The month is also characterized by considerable precipitation, with 97 mm (3.8 inches) over 11 rainy days and high humidity levels of 84%. In contrast, July experiences milder temperatures, with a minimum of 11°C (52°F), an average of 17°C (63°F), and a maximum of 29°C (84°F). This month sees minimal rainfall at just 2 mm (0.1 inches) and no rain days, along with a lower humidity of 70%. For a detailed look at what to expect in July, check out Mendocino weather in July.

December weather is marked by cooler temperatures, with minimums around 2°C (35°F) and average highs reaching 20°C (68°F). This month also experiences considerable precipitation, averaging 97 mm (3.8 in) over about 11 days, contributing to a high humidity of 84%. In contrast, August boasts mild temperatures, with minimums at 11°C (51°F) and average highs of 31°C (88°F). This month is notably dry, with only 1 mm (0.0 in) of rainfall and no precipitation days, resulting in a lower humidity of 66%. For further details on August weather, you can check out Mendocino weather in August.

In December, the weather is significantly cooler with average temperatures ranging from 2°C (35°F) to a maximum of 20°C (68°F), while September boasts a warmer climate with temperatures between 8°C (47°F) and 36°C (96°F). December also sees higher humidity levels at 84% compared to September's more comfortable 68%. The month of December experiences more precipitation, with a total of 97 mm (3.8 in) spread over 11 days, whereas September is much drier, with just 6 mm (0.2 in) of rainfall in only 1 day. For a closer look at Mendocino's September climate, visit Mendocino weather in September.

When comparing the weather in December to October, several significant differences emerge. In December, temperatures are cooler, ranging from a minimum of 2°C (35°F) to a maximum of 20°C (68°F), with an average of 10°C (50°F). The month also sees increased precipitation, averaging 97 mm (3.8 in) over approximately 11 days, and higher humidity levels at 84%. In contrast, October boasts milder conditions with a wider temperature range of 6°C (43°F) to 32°C (90°F) and an average of 15°C (60°F). Additionally, October experiences less rainfall, totaling 43 mm (1.7 in) over only 3 days, along with lower humidity at 72%. For more detailed insights into October's climate, you can check Mendocino weather in October.

When comparing the weather in December to that of November, we see some notable differences. December's temperatures range from a minimum of 2°C (35°F) to a maximum of 20°C (68°F), averaging at 10°C (50°F), which is slightly cooler than November's minimum of 1°C (34°F), maximum of 22°C (72°F), and an average of 12°C (53°F). Additionally, December experiences more precipitation, with 97 mm (3.8 in) over 11 days, compared to November's 72 mm (2.8 in) over just 6 days. Despite comparable humidity levels of 84%, December tends to feel wetter and cooler than November. For more insights on November's weather, you can explore Mendocino weather in November.

Compare Mendocino's Climate with Cities Worldwide

Conclusion: What to Expect From December Weather in Mendocino

December in Mendocino heralds a notable shift in weather patterns, characterized by cooler temperatures and increased precipitation compared to other months. As the holiday season approaches, the average chill in the air invites cozy gatherings, while the likelihood of rain adds a refreshing, lively touch to the lush landscapes. With humidity levels peaking, the coastal charm intensifies, enveloping the region in a mysterious fog at times, and enriching the vibrant greenery. For those seeking to explore or simply enjoy this tranquil winter atmosphere, understanding the unique qualities of December is essential. To learn more about how the weather plays out throughout the year, explore Mendocino Climate.