December Weather in San Diego, Mexico

Last updated: April 22, 2025

Experience the enchanting December weather of San Diego, Mexico, where temperatures range from a comfortable 10°C (51°F) at night to a warm 34°C (93°F) during daytime. With an average temperature of 21°C (70°F), this month offers the perfect balance for outdoor activities. Although December sees some precipitation, with only 17 mm (0.7 in) spread over 2 days, the humidity remains high at 86%, creating a tropical ambiance. Embrace the moderate climate and enjoy the vibrant surroundings of San Diego this month!

December Temperature in San Diego

In December, San Diego, Mexico, offers a comfortable climate as the year draws to a close. With minimum temperatures around 10°C (51°F), the nights are pleasantly cool, while average daytime highs reach 34°C (93°F), creating an inviting atmosphere for outdoor activities. This month showcases a gentle transition from the warmer months, with average temperatures settling at 21°C (70°F), which is a delightful balance for both locals and visitors. The consistently mild weather ensures that December remains a favored time for exploration, whether strolling along the coast or enjoying the local culture. Overall, the month's temperature trend indicates a shift towards cooler evenings paired with warm days, making it an ideal winter escape.

December Weather in San Diego: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in San Diego, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec676971757984858483827670
Data source: Temperature data for San Diego 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 San Diego

In December, San Diego, Mexico, experiences a shift in its precipitation patterns as the year comes to a close. With an average rainfall of 17 mm (0.7 in) over just 2 days, December marks a notable reduction compared to the summer months, which are characterized by substantial rainfall. Following an impressive peak in August with 152 mm (6.0 in), the city's weather transitions into its drier season, offering a brief reprieve from the heavier downpours. As November finishes with 46 mm (1.8 in), December's precipitation reflects a steady decline, highlighting the region's seasonal variability while still providing a refreshing end to the year. The patterns indicate a clear pattern of decreased precipitation leading into the cooler, drier months, inviting residents and visitors to enjoy outdoor activities amidst a milder climate.

December Precipitation Trends in San Diego

The chart displays monthly precipitation patterns in San Diego, 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.
JanFebMarAprMayJunJulAugSepOctNovDec6242002686152143434617
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in San Diego

December marks a notable peak in humidity in San Diego, Mexico, with levels reaching 86% as the year comes to a close. Following a steady increase from the milder months of April and May, humidity levels begin to rise significantly during the summer, culminating in August's high of 87%. This trend continues into the fall, with November also exhibiting elevated humidity at 84%. As December arrives, the air remains rich with moisture, reflecting the region's transition from the dry, warm months to the cooler winter season, and highlighting the often damp conditions that can characterize this time of year.

December Average Humidity in San Diego

This chart illustrates the average monthly humidity levels in San Diego, 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.
JanFebMarAprMayJunJulAugSepOctNovDec76%69%57%49%49%64%82%87%88%83%84%86%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in San Diego

In December, San Diego experiences a UV Index of 6, placing it in the high exposure category, with a burn time of 25 minutes. This marks a gradual decline from the previous months, where the UV Index reached its peak in the spring and summer with values soaring to 13. As the year comes to a close, December offers a respite from the extreme levels seen from March through November, as shorter days and cooler weather contribute to lower UV radiation. However, it is still essential to remain mindful of sun exposure during this month. For more detailed information on the UV Index throughout the year, visit San Diego UV Index.

Maximum UV Index Levels in San Diego for December

The chart shows the monthly maximum UV Index (UVI) for San Diego 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.
JanFebMarAprMayJunJulAugSepOctNovDec710111313121212121186
Data source: San Diego 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 San Diego

In San Diego, Mexico, December is a delightful month, boasting 273 hours of sunshine that ensure the festive season sparkles with warmth. As a transition from the cooler fall months, December mirrors the sunny disposition established in the preceding months of late summer and early autumn, where sunshine peaks in May at 360 hours. Following May, the daylight hours gradually recede, yet December's total remains pleasantly significant, hinting at an irresistible charm as the region embraces the holiday spirit. Overall, the trend reveals a rich tapestry of brilliant sunlight, making San Diego a captivating destination even in the heart of winter.

Monthly Sunshine Duration in San Diego: December Highlighted

The December sunshine duration represents the total number of hours San Diego 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.
JanFebMarAprMayJunJulAugSepOctNovDec222h259h308h325h360h334h319h296h278h298h272h273h
Data source: San Diego December Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in San Diego During December

When considering the likelihood of sunny weather in December in San Diego, Mexico, the statistics reveal a moderate 57% chance of sun. While this suggests a good possibility of enjoying sunny days, it follows a notable trend throughout the year. The sunniest months occur earlier — with May peaking at a striking 80% chance — while June and July experience a significant drop to 56% and 40%, respectively. Interestingly, the chances begin to rebound slightly in October and November, yet December settles back into a more average 58% when compared to the year's overall fluctuations. This means that while you may need to keep an eye on the forecast, there's still a decent shot at basking in some winter sunshine.

Percentage of Sunny Days in December in San Diego

The chart illustrates the percentage of sunny days in San Diego 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 San Diego experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec65%61%57%65%80%56%40%21%40%75%62%57%
Data source: San Diego December chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in San Diego in December

In San Diego, Mexico, the daylight duration offers a fascinating glimpse into the changing seasons throughout the year. Starting in January, residents experience about 10 hours of daylight, which gradually increases until it peaks in May and June with a full 13 hours. As summer begins to wane, daylight slowly diminishes, returning to 12 hours in August and September, then further tapering off to 11 hours in October. By the time December rolls around, daylight hours settle back to 10, echoing the year’s beginning. This cyclical pattern highlights the region's mild shifts in daylight, making each season uniquely charming while maintaining a steady rhythm that locals and visitors alike have come to cherish.

Average Daylight Hours in San Diego for December

The chart illustrates the variation in daylight duration in San Diego throughout the year, with December highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 47m11h 19m12h 1m12h 44m13h 19m13h 37m13h 27m12h 56m12h 15m11h 32m10h 56m10h 37m
Data source: San Diego daylight hours, calculated by summing the hours between sunrise and sunset for each day.

December Winds in San Diego

As winter descends upon San Diego, Mexico, December sees the average wind speed settle at 1.8 m/s (4 mph), a slight dip from the more active months of March and June. This month marks a gentle transition from the cooler, breezier late fall, where wind slightly strengthened as the year closed. Throughout the year, the wind speed has varied, with July and August experiencing the calmest conditions, while the spring months boasted more lively gusts. Overall, as temperatures cool off and the festive spirit grows, the tranquil December winds provide a soothing backdrop to life in this coastal haven.

Average December Wind Speed in San Diego

The chart displays monthly wind speed patterns in San Diego, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1.91.82.11.92.02.11.61.51.41.61.71.8 m/s
Data source: San Diego December wind data, generated using information from the Copernicus Climate Change Service.

How December Weather in San Diego Compares to Other Months

The weather in San Diego 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 Diego and find detailed weather information for every month.

In December, temperatures in the region range from a minimum of 10°C (51°F) to a maximum of 34°C (93°F), with an average of 21°C (70°F). The month experiences relatively high humidity at 86% and sees about 17 mm (0.7 in) of precipitation over two days. In contrast, January brings slightly cooler temperatures, with a minimum of 8°C (47°F) and a maximum of 33°C (91°F), averaging 20°C (68°F). Precipitation significantly decreases to just 6 mm (0.3 in) over one day, and humidity also drops to 76%. For more details, check out the San Diego weather in January.

In December, temperatures range from a minimum of 10°C (51°F) to a maximum of 34°C (93°F), with an average of 21°C (70°F). The month experiences low precipitation, totaling 17 mm (0.7 in) over just 2 days, accompanied by a high humidity level of 86%. Conversely, February sees slightly cooler temperatures with a minimum of 8°C (47°F) and a maximum of 33°C (92°F), while the average remains close at 20°C (69°F). Precipitation increases to 24 mm (0.9 in) but still occurs over the same 2 days, with humidity dropping to 69%. Overall, February is a bit wetter and less humid compared to December. For more details, check San Diego weather in February.

In December, the weather is characterized by slightly cooler temperatures, with an average of 21°C (70°F) and maximum highs reaching up to 34°C (93°F). The month experiences higher humidity at 86% and receives about 17 mm (0.7 in) of precipitation over two days. In contrast, March presents a warmer average temperature of 22°C (72°F), with similar maximum temperatures but significantly less humidity at 57%. Additionally, March boasts minimal precipitation, with only 2 mm (0.1 in) recorded over zero rainy days. For a more detailed look at conditions, check out San Diego weather in March.

In December, the weather is generally warm, with temperatures ranging from a minimum of 10°C (51°F) to a maximum of 34°C (93°F) and an average of 21°C (70°F). The humidity is high at 86%, and there is some precipitation, averaging 17 mm (0.7 in) over two days. In contrast, April brings even warmer temperatures, with a minimum of 12°C (53°F), an average of 24°C (75°F), and a maximum of 36°C (97°F). Remarkably, April sees no precipitation, maintaining a dry spell with 0 mm recorded, and the humidity drops significantly to 49%. For a detailed look at San Diego weather in April, visit San Diego weather in April.

December and May present contrasting weather patterns, showcasing the dynamic climate of the region. In December, temperatures range from a mild 10°C (51°F) to a maximum of 34°C (93°F), with an average of 21°C (70°F). The humidity is quite high at 86%, contributing to a somewhat humid feel, along with 17 mm (0.7 inches) of precipitation over two days. In stark contrast, May enjoys warmer temperatures, with a minimum of 15°C (60°F) and a peak of 37°C (98°F), averaging 26°C (80°F). Notably, May experiences no rainfall, leaving the skies clear and the humidity much lower at 49%. For those interested in the specifics of May weather, you can check out San Diego weather in May.

In December, the weather is mild with temperatures ranging from a minimum of 10°C (51°F) to a maximum of 34°C (93°F), averaging around 21°C (70°F). The month sees relatively low precipitation, with only 17 mm (0.7 in) measured over about two days and high humidity at 86%. In contrast, June experiences warmer conditions, featuring a minimum temperature of 20°C (68°F) and a maximum of 38°C (100°F), with an average of 29°C (84°F). While June has more precipitation at 26 mm (1.0 in) over three days, the humidity is notably lower, at 64%. For those interested in more details about the climate during June, you can visit San Diego weather in June.

In December, temperatures range from a mild 10°C (51°F) at night to a warm 34°C (93°F) by day, with an average of 21°C (70°F). The month is relatively dry, receiving only 17 mm (0.7 in) of precipitation over just 2 rain days and enjoying high humidity levels of 86%. In contrast, July experiences significantly warmer conditions, with minimum temperatures of 23°C (74°F), averaging 29°C (85°F), and peaking at a scorching 37°C (100°F). The rainfall in July is much greater at 86 mm (3.4 in), spread across 14 days, contributing to slightly lower humidity at 82%. For more details on the weather in July, visit San Diego weather in July.

In comparing the weather of December and August, December offers a milder climate with temperatures ranging from a minimum of 10°C (51°F) to a maximum of 34°C (93°F), averaging 21°C (70°F). Precipitation is minimal during this month, accumulating only 17 mm (0.7 in) across just 2 days, with humidity levels at 86%. In contrast, August is significantly hotter, with temperatures starting at a minimum of 23°C (75°F) and peaking at 37°C (98°F), resulting in an average of 29°C (85°F). Rainfall is much more substantial in August, totaling 152 mm (6.0 in) over 19 days, accompanied by a slightly higher humidity of 87%. For more detailed information, you can explore San Diego weather in August.

December and September present contrasting weather conditions. In December, temperatures range from a pleasant minimum of 10°C (51°F) to a warm maximum of 34°C (93°F), with an average of 21°C (70°F). The month sees relatively low precipitation, totaling only 17 mm (0.7 in) over just 2 days, accompanied by high humidity at 86%. In contrast, September is significantly warmer, with a minimum temperature of 23°C (74°F) and a maximum reaching up to 36°C (97°F), averaging at 28°C (83°F). This month experiences much heavier rainfall, accumulating 143 mm (5.6 in) over 20 days, and maintaining slightly higher humidity at 88%. For more insights on September weather, you can visit San Diego weather in September.

In comparing the weather between December and October, December presents a more moderate climate with temperatures ranging from a minimum of 10°C (51°F) to a maximum of 34°C (93°F), averaging around 21°C (70°F). In contrast, October tends to be warmer, with temperatures fluctuating between 18°C (64°F) and 37°C (98°F), and an average of 28°C (83°F). Additionally, October experiences higher precipitation, totaling 43 mm (1.7 in) over 5 days, compared to December's 17 mm (0.7 in) over just 2 days. Notably, while December has slightly higher humidity at 86%, October remains relatively humid at 83%. For a closer look at the specifics, you can visit San Diego weather in October.

In comparing the weather between December and November, December experiences slightly milder temperatures, with a minimum of 10°C (51°F) and a maximum of 34°C (93°F), compared to November's range of 14°C (58°F) to 36°C (98°F). The average temperature in December is around 21°C (70°F), while November's average is higher at 25°C (77°F). Additionally, December sees less precipitation, with only 17 mm (0.7 in) over 2 days, contrasting with November’s 46 mm (1.8 in) during the same number of days. Humidity levels remain relatively high in December at 86%, only slightly above November's 84%. For those interested in understanding more about the weather in November, you can refer to San Diego weather in November.

Compare San Diego's Climate with Cities Worldwide

Conclusion: What to Expect From December Weather in San Diego

As December settles in, San Diego transforms into a mild and pleasantly humid haven, contrasting nicely with the hotter summer months. With average temperatures around 21°C (70°F), the city experiences a comfortable yet cooler climate that invites outdoor exploration. Unlike the more intense summer heat, December's mild temperatures rarely exceed 34°C (93°F) and are often accompanied by a gentle touch of rain, as the city sees about 17 mm (0.7 in) of precipitation spread over just two days. This shift in weather not only enhances the festive spirit but also brings a refreshing respite, making it an ideal time to enjoy the beauty of San Diego. For a deeper dive into the year-round climate, visit San Diego Climate.