San Diego’s Unseasonable Heatwave Continues

San Diego is currently experiencing an unprecedented spell of warm weather for early December, leaving many locals wondering if winter will ever arrive. As of December 12, 2025, we’ve already endured four consecutive days of record-breaking temperatures, with today posing a strong possibility for a fifth straight record, pushing our usually mild December far into summer territory.

The Forecast: Can We Hit Five Record Days?

Today, December 12, marks a pivotal moment in San Diego’s extraordinarily warm December. Forecasters are closely monitoring conditions to determine if we will indeed log a fifth consecutive day of record-high temperatures. This persistent heat is highly unusual for this time of year, disrupting the typical pattern of cooler coastal breezes and crisp, clear skies that San Diegans usually associate with the holiday season.

While specific temperature predictions for today remain elevated, hovering significantly above the seasonal average, residents should prepare for continued abundant sunshine and minimal marine layer intrusion. The robust and extensive high-pressure system dominating the entire Southwestern region is the undeniable primary driver behind this extended heat streak, effectively acting as an atmospheric barrier that blocks any potential influx of cooler air from the vast Pacific Ocean from reaching our immediate coastline.

Unpacking the Warm Spell’s Causes

Meteorological experts attribute San Diego’s current prolonged heatwave to a particularly stubborn and expansive ridge of high pressure entrenched over the Southwest. This dominant atmospheric configuration functions much like an enormous, invisible dome, efficiently trapping warm air beneath it and simultaneously preventing any cooler, more moist air originating from the Pacific Ocean from migrating inland. While San Diego is globally renowned for its perpetually mild and desirable climate, these current December temperatures are exceptionally atypical, bearing a striking resemblance to conditions one might expect in late summer or early autumn rather than the cusp of winter, making for a truly jarring and unexpected deviation from traditional holiday season weather expectations.

Adding to the dry, warm conditions is the distinct absence of any significant rainfall, which would typically help to moderate temperatures. Although often associated with specific warming events like Santa Ana winds, a powerful and stable high-pressure system, even without the strong Santa Ana gusts, can still generate similar warming effects, particularly in sustaining elevated daytime temperatures consistently across the entirety of San Diego County.

Comparing Current vs. Typical December Temperatures

To provide a clear context for this current heatwave, let’s examine how the prevailing daily high temperatures dramatically contrast with what San Diegans traditionally anticipate and experience during the first half of December:

As the comparative table vividly illustrates, San Diego is currently experiencing temperatures that are consistently more than 10 to 15 degrees Fahrenheit above the established seasonal average. This significant deviation isn’t just a marginal increase; it represents a profound shift, actively setting new historical benchmarks for warmth during what is traditionally one of the cooler months of the year. This dramatic climatic anomaly has tangible and widespread effects on various aspects of daily life, ranging from elevated water usage to the unique adjustments San Diegans are making to their holiday planning and outdoor activities.

Implications for San Diegans’ Daily Life

This unusually prolonged period of warmth carries several distinct consequences for both long-time residents and visiting tourists. While the extended opportunity for beach days is certainly appealing to many, the sheer duration and intensity of this heat are beginning to raise broader concerns across the community:

Enjoying the Outdoors Responsibly

With abundant sunny skies and persistently warm temperatures defining our current weather, San Diego’s iconic beaches, sprawling parks, and scenic hiking trails remain incredibly popular. However, it is absolutely paramount for everyone to prioritize safety above all else. Maintaining adequate hydration is crucial, especially for individuals engaging in any form of outdoor activity. Always remember to apply broad-spectrum sunscreen liberally, wear wide-brimmed hats, and opt for lightweight, breathable clothing to ensure maximum protection against sun exposure, which can be surprisingly potent and deceptive even in early December.

Families diligently planning their cherished holiday outdoor gatherings might find themselves making significant adjustments to their menus and activity schedules to better suit the warmer climate. This could involve choosing refreshing cold appetizers and salads over traditional warm, heavy dishes, or strategically seeking out naturally shaded areas and gazebos instead of congregating on sun-drenched patios.

Impact on Energy Consumption and Resource Management

The consistent and unseasonal need for air conditioning, even during what should be a cooler December, is inevitably leading to a noticeable surge in energy consumption for numerous households and businesses throughout San Diego County. This increased demand places considerable strain on the local power grid, prompting utility providers and local authorities to issue timely reminders and appeals for voluntary energy conservation wherever and whenever possible. Furthermore, prolonged periods of dry heat can significantly exacerbate existing drought conditions, rendering water conservation efforts even more critically important and urgent for our already parched region.

What to Watch Next: A Glimmer of Change?

The prevailing question on virtually everyone’s mind is understandably: when will this exceptionally stubborn heatwave finally break? Forecasters are cautiously anticipating a very gradual and subtle shift in the overall weather pattern as we head into the upcoming weekend and the early part of next week. While an abrupt and immediate return to typical crisp December chill is not currently projected, we may start to observe a welcome, albeit slight, decrease in temperatures, potentially falling back into the more manageable low to mid-70s range.

Residents are advised to continuously monitor official weather reports and local news for any emergent signs of a developing marine layer, which typically brings cooler, moister air, or a more significant atmospheric trough moving into the region. Such developments would herald much-needed cooling and potentially even some welcome, albeit elusive, precipitation. Until these changes materialize, the unseasonably warm spell regrettably continues to define and dominate our early December in San Diego.

Frequently Asked Questions About San Diego’s December Heatwave

• Why is San Diego experiencing such high temperatures in December?
  A particularly strong and persistent high-pressure system positioned over the Southwest is effectively trapping warm air, preventing any cooler air masses from reaching our region. This atmospheric setup is unusually robust and long-lasting for this specific time of year.
• What are the main health and safety risks during this unseasonal heat?
  The primary health risks include severe dehydration, heat exhaustion, and painful sunburn. Residents should also be aware of a heightened, albeit not extreme, fire danger in dry brush areas due to the prolonged dry heat, though the immediate risk isn’t as critical as during typical strong Santa Ana wind events.
• How long is this unprecedented heatwave expected to last?
  While today, December 12, could potentially mark the fifth consecutive record-breaking day, forecasters are predicting a gradual moderation in temperatures over the coming days, meaning conditions will likely remain warmer than average through the upcoming weekend.
• Are these record-breaking temperatures normal for San Diego in December?
  Absolutely not. December in San Diego typically features average high temperatures in the mid-to-high 60s°F. The current temperatures, consistently hovering around the low 80s°F, are profoundly and significantly above all seasonal norms and are actively establishing new historical records for the month.
• What should I do if I or someone I know experiences symptoms of heat exhaustion?
  Move immediately to a cooler, shaded place. Loosen clothing, apply cool, wet cloths to the body (especially face and neck), and sip water slowly. If symptoms worsen (e.g., confusion, fainting, severe vomiting), seek immediate medical attention or call 911.

As San Diego navigates this truly remarkable and historic December heatwave, it is crucial to remember key safety precautions: stay diligently hydrated, protect yourself proactively from the intense sun, and embrace the unique opportunity for warm-weather outdoor activities responsibly and cautiously until more characteristic seasonal temperatures finally make their welcome return to America’s Finest City.

San Diego Unseasonable Heatwave Eyes Fifth Record Day