Last updated: February 24, 2025
December in San Marcos, United States showcases a diverse range of weather experiences. With a maximum temperature soaring to 29°C (84°F) and a chilly minimum of -3°C (27°F), residents enjoy the seasonal contrasts. The average temperature hovers around a comfortable 13°C (55°F). Rainfall is modest, totaling 73 mm (2.9 in) across approximately seven days, contributing to an impressive humidity level of 86%. This blend of warmth and coolness, along with occasional showers, defines a dynamic December for the community.
In December, San Marcos experiences a transitional shift as temperatures begin to dip following the warmer months. The minimum temperature hovers around a brisk -3°C (27°F), while the average settles at a cool 13°C (55°F), providing a refreshing end to the year. The maximum can still reach a mild 29°C (84°F), illustrating a stark contrast to January's chill. This month marks a significant drop compared to the preceding warmer months, with a notable decrease from November's highs. Residents enjoy mild afternoons paired with cooler evenings, making December an ideal time for cozy gatherings and outdoor festivities under the crisp winter sky.
In December, San Marcos experiences a moderate increase in precipitation, with 73 mm (2.9 in) of rainfall occurring over 7 days. This marks a slight drop from the heavier rains of late spring, especially May's peak of 149 mm, but remains consistent with the city's trend of frequent precipitation throughout the cooler months. Notably, December's rainfall contributes to a well-balanced climate, bridging the gap between the dry spells of summer and the lush growth of spring. As the year closes, this month’s precipitation reflects a transition phase, preparing the landscape for the upcoming seasonal changes while maintaining the region’s vibrant ecosystem.
As the year comes to a close, December in San Marcos ushers in a notable increase in humidity, reaching a substantial 86%. This marks a significant rise from the more temperate levels earlier in the year, especially when compared to the summer months, which saw July and August at their driest, with humidity dipping to 66% and 58%, respectively. The trend reveals a curious ebb and flow; after a peak in May at 81%, humidity levels fluctuated through the warmer months before surging again as winter approaches. November, mirroring May’s moisture, lays the groundwork for December's humidity spike, making the end of the year in San Marcos notably humid and inviting a cozy, refreshing atmosphere as the holiday season unfolds.
In December, San Marcos experiences a moderate UV Index of 5, marking a shift from the intense sun exposure of the summer months. As temperatures drop and the holiday season approaches, residents can enjoy an extended burn time of 30 minutes before needing sun protection. The UV Index trend in San Marcos throughout the year showcases a peak from April to September, where values soar to an extreme level of 12, necessitating urgent caution for sun exposure. Interestingly, the UV Index drops back down to a more manageable level in the cooler months of January and December, inviting a welcome respite from the earlier intensity. For more detailed information on UV trends, please visit San Marcos UV Index.
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December in San Marcos basks in a warm glow with 223 hours of sunshine, a delightful farewell to the year. As the months progress toward winter, sunshine gradually diminishes from the sunny peaks of July's impressive 348 hours down to December's more subdued but still generous light. After a radiant spring and early summer, where days often exceed 320 hours, December offers a cozy, sunlit ambiance that invites residents and visitors alike to embrace the seasonal change. While the sunshine may be less abundant than in mid-year, it still provides a comforting backdrop for festive gatherings and outdoor adventures, reminding us that even in winter, the sun remains a cherished companion in San Marcos.
In San Marcos, the likelihood of sunny weather in December tends to be on the lower end, with only a 37% chance of sunshine. This marks a significant dip compared to the more favorable conditions of earlier months like January and November, which boast chances of 58% and 57%, respectively. Interestingly, as the year progresses towards December, a downward trend emerges, peaking in September at 59% but gradually declining through the colder months. This pattern suggests that while December can still surprise with a few sunny days, residents and visitors should prepare for more overcast skies as the year comes to a close.
As December settles in San Marcos, the daylight duration mirrors the waning light of the year, providing 10 hours of daylight. This marks a shift from the peak of summer in June, when the days stretch to a generous 14 hours. As the calendar moves through the seasons, daylight gradually decreases, with January and November also seeing 10 hours each. The transition to longer days begins in February, increasing steadily until May, when daylight reaches its annual high. This cyclical pattern not only highlights the charm of the changing seasons but also invites residents to embrace the beauty of the winter months, as the shorter days create a perfect backdrop for cozy evenings and festive gatherings.
In December, San Marcos experiences a return to slightly brisker winds, with an average wind speed of 3.4 m/s (8 mph). This marks a resurgence after several months of lighter breezes during the summer, where speeds dipped to a calm 2.5 to 2.9 m/s (6 mph) from June to September. As autumn settles in, there is a steady increase, culminating in December's winds that echo the more invigorating speeds seen at the year's start. The transition from November's average of 3.2 m/s (7 mph) to December brings a refreshing chill, inviting residents to wrap up warmly while enjoying the vibrant, dynamic atmosphere of the season. Overall, December's winds serve as a gentle reminder of the refreshing changes winter brings to San Marcos.
The weather in San Marcos 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 Marcos and find detailed weather information for every month.
December and January present notable differences in weather patterns. December typically enjoys a wider temperature range with a minimum of -3°C (27°F) and an average of 13°C (55°F), peaking at 29°C (84°F). It also experiences relatively high humidity at 86% and a total precipitation of 73 mm (2.9 in) over approximately 7 days. In contrast, January is cooler, showcasing a minimum temperature of -7°C (19°F) and averaging 11°C (52°F), with a maximum of 26°C (80°F). It sees less precipitation at 48 mm (1.9 in) across about 6 days and lower humidity at 79%. For a closer look at weather patterns, check out San Marcos weather in January.
In December, temperatures in San Marcos range from a chilly minimum of -3°C (27°F) to a more comfortable average of 13°C (55°F), with maximum highs reaching up to 29°C (84°F). The month sees about 73 mm (2.9 in) of precipitation over approximately 7 days, accompanied by high humidity at 86%. In contrast, February experiences colder nights with a minimum of -15°C (6°F), yet slightly warmer average temperatures at 12°C (54°F) and maximums peaking at 31°C (87°F). Precipitation decreases to 60 mm (2.4 in) but occurs on more days, totaling around 10 days, while humidity lowers to 79%. For more detailed information, check out San Marcos weather in February.
In comparing the weather between December and March, both months experience a minimum temperature of -3°C (27°F), but March boasts a significantly warmer average temperature of 17°C (64°F) compared to December's 13°C (55°F). The maximum temperatures also show a marked difference, with March reaching a high of 33°C (91°F), whereas December peaks at 29°C (84°F). Precipitation is somewhat similar, with December receiving 73 mm (2.9 in) over 7 days and March slightly less at 67 mm (2.6 in) over 11 days. Notably, humidity levels are higher in December at 86%, while March offers a drier atmosphere with 74% humidity. For more detailed insights, visit San Marcos weather in March.
December weather is characterized by cooler temperatures, with a minimum of -3°C (27°F) and an average of 13°C (55°F), while the maximum can reach up to 29°C (84°F). This month also sees a higher humidity level of 86% and around 73 mm (2.9 inches) of precipitation over about 7 days. In contrast, April brings warmer conditions, with temperatures ranging from a minimum of 3°C (38°F) to an average of 20°C (69°F) and a peak of 35°C (94°F). Although it is slightly wetter with 89 mm (3.5 inches) of rainfall over 9 days, the humidity drops to 76%. For more detailed information about April weather, you can check San Marcos weather in April.
In comparing the weather between December and May, it's clear that May brings much warmer temperatures, with minimums at 10°C (51°F) compared to December's chilly -3°C (27°F). The average temperatures also show a significant shift, rising from 13°C (55°F) in December to a comfortable 25°C (76°F) in May. Additionally, May can see highs reaching up to 36°C (98°F), while December’s maximum is only 29°C (84°F). However, May has more rainfall, with 149 mm (5.9 in) over about 14 days, compared to December's 73 mm (2.9 in) in just 7 days. Interestingly, humidity levels are slightly lower in May at 81%, compared to December’s higher 86%. For more details on May weather, you can visit San Marcos weather in May.
December and June showcase strikingly different weather patterns. In December, temperatures can dip as low as -3°C (27°F) and reach a comfortable average of 13°C (55°F), with a maximum of 29°C (84°F). This month sees a higher humidity level at 86% and approximately 73 mm (2.9 in) of precipitation over about 7 days.
In contrast, June brings much warmer conditions, with minimum temperatures around 17°C (63°F) and soaring averages of 27°C (82°F), peaking at a sweltering 37°C (100°F). While June experiences more rainfall at 102 mm (4.0 in) across roughly 12 days, the humidity is relatively lower at 76%. For a detailed look at weather conditions in June, visit San Marcos weather in June.
The weather in December contrasts significantly with that of July. In December, temperatures rarely dip below -3°C (27°F) and can reach a comfortable average of 13°C (55°F), with maximums peaking at 29°C (84°F). However, the month is also marked by higher humidity (86%) and about 73 mm (2.9 in) of precipitation over approximately 7 days. In stark contrast, July boasts much warmer minimum temperatures, starting at 17°C (63°F) and averaging 29°C (84°F), with maximums soaring up to 41°C (106°F). Although July sees slightly more precipitation at 79 mm (3.1 in) over about 9 days, its lower humidity (66%) contributes to a more arid feel compared to the winter month. For more details on July weather, visit San Marcos weather in July.
When comparing the weather in December and August, the contrasts are striking. December experiences cooler temperatures, with a minimum of -3°C (27°F) and averages around 13°C (55°F), experiencing maximums reaching 29°C (84°F). It also has higher humidity levels at 86% and receives around 73 mm (2.9 in) of precipitation over about 7 days. In contrast, August is significantly warmer, with a minimum temperature of 20°C (68°F) and averages soaring to 29°C (85°F), peaking at a high of 40°C (104°F). This summer month has a bit more rainfall at 111 mm (4.4 in) but with lower humidity at 58%. For more details on the specific climate conditions, you can check out San Marcos weather in August.
In comparing the weather of December and September, it's clear that the two months present distinct experiences. December features a cooler temperature range, with lows dropping to -3°C (27°F) and average highs around 13°C (55°F), whereas September boasts much warmer temperatures, with lows of 11°C (53°F) and maximums reaching a sweltering 38°C (100°F). Additionally, December's humidity is quite high at 86%, contributing to a chillier atmosphere, while September maintains a lower humidity level of 65%, making the heat feel more intense. Precipitation is also notable; December receives about 73 mm (2.9 in) over 7 days, compared to September's heavier rainfall of 112 mm (4.4 in) over 11 days. For more on September weather, you can check San Marcos weather in September.
In comparing the weather between October and December, we notice significant differences in temperature and precipitation. October features a milder climate with minimum temperatures around 3°C (37°F) and an average of 21°C (70°F), reaching highs of 35°C (96°F). In contrast, December is considerably cooler, with lows dropping to -3°C (27°F) and an average temperature of 13°C (55°F), peaking at 29°C (84°F). Additionally, October experiences higher total precipitation at 94 mm (3.7 in) over about 10 days, compared to December's 73 mm (2.9 in) across 7 days. The humidity is also notable, with October at 74% compared to December's higher 86%. For a more detailed look at the October weather, you can check San Marcos weather in October.
Comparing the weather in December to November, both months experience similar minimum temperatures, hovering around -3°C (27°F). However, December tends to be slightly cooler on average, with an average temperature of 13°C (55°F), compared to November's warmer average of 15°C (60°F). The maximum temperatures are also marginally lower in December, reaching up to 29°C (84°F) versus November's high of 30°C (86°F). In terms of precipitation, December sees an increase with 73 mm (2.9 in) over 7 days, compared to November’s 49 mm (1.9 in) across 6 days. Humidity levels are notably higher in December at 86%, compared to 81% in November, creating a more humid atmosphere during the later month. For more detailed information, check out San Marcos weather in November.
December in San Marcos presents a distinctive shift in weather patterns compared to other months. The temperatures dip significantly, showcasing cooler days and crisp nights, creating a cozy atmosphere ideal for holiday festivities. With average highs giving way to a chillier feel, residents and visitors alike find solace in warmer clothing. Additionally, the month experiences a noticeable increase in humidity, coupled with sporadic precipitation, painting a picturesque but sometimes damp holiday backdrop. This combination of cooler temperatures and refreshing rain makes December a unique time to experience the charm of San Marcos. For a deeper dive into the city's weather patterns, explore San Marcos Climate.