Last updated: February 24, 2025
December in San Francisco offers a cool yet inviting climate, with temperatures ranging from a minimum of 4°C (40°F) to a maximum of 20°C (69°F). The average temperature settles at a comfortable 11°C (52°F), creating ideal conditions for outdoor exploration. However, this month also brings moderate rainfall, accumulating to 95 mm (3.7 in) over approximately 9 rainy days, adding a refreshing touch to the city’s vibrant atmosphere. With a humidity level of 79%, the air feels crisp and invigorating, making December a unique time to experience the charm of San Francisco.
In December, San Francisco experiences mild temperatures that reflect a subtle transition towards cooler winter months. With minimums of 4°C (40°F) and maximums around 20°C (69°F), the weather remains relatively comfortable, averaging 11°C (52°F). This pattern continues the trend of winter temperatures that are consistently warmer compared to many other regions, with no dramatic dips, as seen in the previous months. As the year wraps up, the city's climate remains inviting, encouraging locals and visitors alike to explore its iconic streets, albeit with a light jacket in tow. The mild December conditions exemplify San Francisco's unique climate, where chilly winds often give way to sunny afternoons, making for a delightful end to the year.
December in San Francisco marks a notable transition in the city's weather patterns as precipitation levels rise, contributing to the overall wet season. With an average rainfall of 95 mm (3.7 in) over 9 days, December showcases a significant increase compared to the drier summer months, where the city experiences little to no rain. This late fall surge in moisture not only blankets the city in lush greenery but also sets the stage for the wetter months ahead, as January and February follow closely with similar precipitation levels. The trend indicates a clear shift from the previous months' minimal rain, emphasizing the importance of December in replenishing the urban landscape before the new year.
As December arrives in San Francisco, the city enjoys a refreshing drop in humidity, settling at 79%. This level mirrors the lower humidity typically seen in November, marking the transition to a drier winter spell. Throughout the year, humidity levels fluctuate, peaking in the summer months of July and August at an elevated 87%, while the early part of the year tends to maintain a higher average around 81% to 85%. The consistent decline from early autumn to the end of the year signals a gradual shift in the coastal climate, providing residents and visitors a more refreshing, crisp atmosphere during the holiday season.
As December rolls into San Francisco, the UV Index dips back to a moderate level of 3, similar to January and November. During this month, residents and visitors can expect a burn time of around 30 minutes without adequate protection. This trend reflects a seasonal shift where the intensity of UV radiation decreases, contrasting starkly with the peak summer months when the index soared to extremes of 11 in June and July. The transition from the intense solar exposure of late spring and summer to the milder conditions in December reminds us to remain vigilant about sun safety year-round, even in cooler months. For detailed information on UV levels throughout the year, check out San Francisco UV Index.
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In December, San Francisco experiences a distinct transition as daylight begins to wane, offering 194 hours of sunshine. While this marks a dip from the peak brightness of June at a vibrant 355 hours, it's essential to appreciate that December still enjoys more sunshine than its early winter counterparts, like January, with only 151 hours. Interestingly, the city sees a gradual decline from the abundant light of summer, where sunshine averages around 320 hours in August, down to the year's dimmest month. As the year wraps up, while sunshine may be less plentiful, San Francisco's charm remains radiant, inviting residents and visitors alike to embrace the beauty of its crisp winter days.
As December rolls into San Francisco, residents and visitors should brace themselves for the least sunny month of the year, with a modest 33% chance of basking in the sun's rays. This decline in sunny weather is part of a broader trend as we transition from the brighter months of late spring and early summer. Notably, December's sun probability is significantly lower than the peaks seen in May and March, which boast 66% and 62% chances, respectively. With the city’s summer months also dimming, illustrating a typical pattern of variability, December often presents a mix of cool temperatures and overcast skies, reminding us that San Francisco's charm persists beyond its sunny days.
In December, San Francisco experiences a return to shorter days, with daylight lasting about 9 hours. This marks the culmination of the year’s gradual decline in sunlight that begins in June, when the city enjoys up to 14 hours of daylight. Following the peak of summer, daily sunlight decreases steadily through the fall months, reaching its nadir in December. The transition from November's 10 hours to December's 9 highlights a rhythmic pattern of day length that mirrors the changing seasons. As the city ushers in winter, residents are reminded of the cozy, reflective evenings that accompany the shortest days of the year.
As December settles in San Francisco, the average wind speed reaches a brisk 3.9 m/s (9 mph), reflecting a subtle increase compared to the calmer months leading up to it. The winds of late fall, which dipped to a gentle 2.7 m/s (6 mph) in November, gradually build up as winter approaches, signaling a shift in the coastal climate. This uptick in wind speed is part of a broader seasonal trend, where spring and early summer months showcase the strongest breezes, peaking at 5.4 m/s (12 mph) in May. A dynamic patient follows through the year, characterized by a gradual decline into the quieter days of autumn. Thus, while December may not boast the highest gusts, it certainly serves as a reminder that even in cooler months, the winds of San Francisco are a constant companion.
The weather in San Francisco 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 San Francisco and find detailed weather information for every month.
December and January share similar average temperatures, with December experiencing a minimum of 4°C (40°F) and a maximum of 20°C (69°F), while January sees slightly cooler nights with a minimum of 3°C (38°F) and a peak of 21°C (70°F). Both months have an average temperature of 11°C (52°F), but January tends to be slightly wetter, with 106 mm (4.2 in) of precipitation compared to December's 95 mm (3.7 in), although both months register precipitation on about 9 days. Additionally, January has a higher humidity level at 85%, compared to December’s 79%, making the start of the year feel a bit wetter overall. For more detailed information, you can check out San Francisco weather in January.
In comparing the weather between December and February, we find that both months experience a similar temperature range, with minimums around 4°C (40°F), averages at 11°C (52°F), and maximums reaching up to 20°C (69°F). However, February tends to be a bit wetter, with total precipitation at 109 mm (4.3 in) compared to December’s 95 mm (3.7 in), despite both months having about 9 days of rainfall. Additionally, February's humidity is slightly higher at 82% versus December's 79%. For a more detailed look at climate specifics, check out San Francisco weather in February.
In December, temperatures in San Francisco range from a minimum of 4°C (40°F) to a maximum of 20°C (69°F), with an average temperature of 11°C (52°F). The month experiences about 95 mm (3.7 in) of precipitation over approximately 9 days, and humidity levels are around 79%. In contrast, March sees slightly higher temperatures, with a minimum of 5°C (42°F) and an average of 12°C (53°F), maintaining the same maximum of 20°C (69°F). Rainfall in March is lower, totaling 78 mm (3.1 in) over about 10 days, with a slightly higher humidity of 82%. For a more detailed look at typical weather patterns, you can explore San Francisco weather in March.
In December, the weather is cooler, with temperatures ranging from a minimum of 4°C (40°F) to a maximum of 20°C (69°F), resulting in an average of 11°C (52°F). This month also experiences higher precipitation, totaling 95 mm (3.7 in) over 9 days, while maintaining a consistent humidity level of 79%. In contrast, April brings milder temperatures, with a minimum of 7°C (44°F) and a maximum reaching 28°C (82°F), leading to an average of 13°C (55°F). Rainfall is significantly reduced to 35 mm (1.4 in) across just 5 days, yet the humidity remains at 79%. For more detailed insights into the specific conditions, check out San Francisco weather in April.
In December, the weather is generally cooler, with temperatures ranging from a minimum of 4°C (40°F) to a maximum of 20°C (69°F) and an average of 11°C (52°F). This month also sees considerable precipitation, with about 95 mm (3.7 in) falling over approximately 9 days, contributing to a humidity level of 79%. In contrast, May experiences milder temperatures, with a minimum of 8°C (47°F) and a maximum of 24°C (75°F), averaging around 14°C (57°F). Rainfall significantly decreases during May, totaling only 20 mm (0.8 in) over just 2 days, and the humidity climbs slightly to 83%. For a detailed overview of weather patterns, visit San Francisco weather in May.
When comparing the weather in December and June, we see a notable difference in temperature and precipitation. December features cooler temperatures, with a minimum of 4°C (40°F) and a maximum of 20°C (69°F), while June enjoys a warmer range, with temperatures ranging from a minimum of 10°C (51°F) to a maximum of 31°C (88°F). Precipitation is much heavier in December, averaging 95 mm (3.7 in) over about 9 days, compared to June, which is typically dry with just 3 mm (0.1 in) of rain and no rainy days. Humidity levels are somewhat similar, with December at 79% and June slightly higher at 84%. For those interested in the specifics of June weather, you can check out San Francisco weather in June.
December and July in San Francisco present stark contrasts in weather conditions. In December, temperatures range from a minimum of 4°C (40°F) to a maximum of 20°C (69°F), with an average of 11°C (52°F). This month also sees significant precipitation, totaling 95 mm (3.7 in) over about 9 days, coupled with a humidity level of 79%. In contrast, July features milder temperatures with a minimum of 11°C (52°F) and a maximum of 24°C (76°F), averaging 15°C (60°F). Precipitation is minimal in July, with only 3 mm (0.1 in) and no rainy days, highlighting a much drier atmosphere despite slightly higher humidity at 87%. For more detailed information, check out San Francisco weather in July.
In December, temperatures in San Francisco range from a minimum of 4°C (40°F) to a maximum of 20°C (69°F), with an average of 11°C (52°F). The month sees significant rainfall, totaling 95 mm (3.7 in) over about 9 days, and humidity levels hover around 79%. In contrast, August experiences a milder climate, with temperatures varying from a minimum of 11°C (53°F) to a maximum of 27°C (81°F) and an average of 16°C (61°F). Remarkably, August is characterized by very little precipitation, receiving only 2 mm (0.1 in) on no rainy days, and slightly higher humidity at 87%. For more detailed insights, check out San Francisco weather in August.
The weather in December is notably cooler than in September, with average temperatures ranging from a minimum of 4°C (40°F) to a maximum of 20°C (69°F), compared to September's warmer averages of 11°C (51°F) to 35°C (96°F). Additionally, December is marked by increased precipitation, receiving about 95 mm (3.7 in) over nine days, while September boasts a dry climate with just 2 mm (0.1 in) of rain, occurring over no days. Humidity levels are slightly higher in September at 86%, compared to December's 79%. For more details about September’s weather, check out San Francisco weather in September.
In comparing the weather between October and December, notable differences emerge. October typically boasts warmer temperatures, with an average of 16°C (60°F), while December sees a cooler average of 11°C (52°F). Additionally, October often features maximum temperatures reaching up to 28°C (84°F), compared to December's peak of 20°C (69°F). Precipitation also varies significantly; October experiences just 30 mm (1.2 in) of rain over 2 days, while December is considerably wetter, accumulating 95 mm (3.7 in) over 9 days. Humidity levels remain relatively consistent, with October at 80% and December slightly lower at 79%. For more details on October weather, you can visit San Francisco weather in October.
When comparing the weather in December to November, we can observe a slight dip in temperatures and an increase in precipitation. December has a minimum temperature of 4°C (40°F) and an average of 11°C (52°F), while November is slightly warmer with a minimum of 6°C (43°F) and an average of 13°C (56°F). Additionally, December experiences more rainfall, with 95 mm (3.7 in) over 9 days, compared to November's 50 mm (2.0 in) over 5 days. Interestingly, both months maintain a consistent humidity level of 79%. For a more detailed look at November's weather, you can visit San Francisco weather in November.
As December sweeps into San Francisco, it brings a refreshing change from the relatively dry and warmer months. The city experiences cooler temperatures, with mild afternoons contrasting against brisk evenings. While average humidity remains high, the increase in precipitation signals the arrival of winter storms, resulting in a wetter atmosphere compared to previous months. This blend of cool weather and rain enhances the city's iconic charm, making it a unique time to explore. For further insights on the city's weather patterns throughout the year, visit San Francisco Climate.