San Diego Weather: Record-Breaking December Heat and Fog Give Way to Christmas Rain

San Diego Sets December Heat Records as County Braces for Atmospheric River Rain

San Diego’s weather in December 2025 has been anything but typical. Over the past few days, the region has seen temperatures soar well above seasonal averages, with several communities shattering daily records. According to ABC 10News meteorologists, places like Alpine and Ramona hit 85°F, while Campo reached 83°F and Lake Cuyamaca 72°F. These readings stand nearly 10 to 20 degrees above what’s expected for mid-December.

What’s even more striking is the wide gap between morning lows and afternoon highs. In Ramona, residents woke up to a chilly 36°F, only to see the thermometer rocket nearly 50 degrees by late afternoon. Such dramatic temperature swings highlight the unusual conditions gripping the county.

Foggy Mornings Disrupt Travel Plans

Adding to the unusual warmth, persistent fog has blanketed coastal and inland areas throughout the week. Meteorologists warn that patchy fog will continue into Friday morning and become more widespread late Friday night and Saturday morning. Sunday morning is also expected to begin in a haze.

This fog isn’t just an inconvenience for commuters; it’s impacting air travel as well. Travelers are urged to check with airlines for potential delays or disruptions, especially those flying out during the peak holiday rush. The combination of dense morning fog and record afternoon heat has made planning unpredictable for locals and visitors alike.

Weekend Weather: Still Warm, But Change Is Coming

Despite a slight cooling trend predicted for Friday—about 5 degrees cooler along the coast and inland—temperatures will remain unseasonably warm, holding at 10 to 20 degrees above average for much of San Diego County. Weekend highs are forecast to settle in the 60s and 70s for most areas, with the mountains and deserts possibly seeing more records fall.

For those seeking a taste of winter, patience is required. The winter solstice arrives Sunday morning at 7:03am, officially ushering in the new season. Yet, the thermometer tells a different story, with San Diego enjoying a warmth more typical of spring.

Christmas Week: Atmospheric River Promises Impactful Rain

But change is on the horizon. The region’s weather pattern is poised to shift dramatically as Christmas approaches. Meteorologists with ABC 10News report that an atmospheric river is expected to sag south through California, bringing widespread and potentially impactful rain to San Diego County.

Showers could begin as early as Tuesday afternoon or evening, but the main event is forecast for Christmas Eve into Christmas Day. The rain may linger into Friday, though forecasters caution that exact timing and rainfall totals remain uncertain this far out. Such atmospheric rivers are known for delivering heavy, sustained precipitation—sometimes enough to test local flood controls and snarl holiday travel.

Local weather teams are monitoring the situation closely, urging residents to stay tuned for updates as the holiday approaches. Whether you’re planning family gatherings or hoping for a winter walk, the coming rain may change how San Diego celebrates the season.

Temperature Outlook: A Closer Look

• Friday’s Highs:
• Coast: 65–74°F
• Inland: 72–81°F
• Mountains: 68–81°F
• Deserts: 80–84°F

These numbers tell the story: even as the calendar turns toward winter, San Diego remains firmly in the grip of a warm spell. Still, the anticipated rainfall may offer a needed break for parched landscapes and a reminder that winter is, in fact, on its way.

Behind the Weather: What’s Driving the Extremes?

While December warmth and fog are not unheard of in Southern California, the scale of this year’s extremes is notable. Meteorologists point to a combination of offshore high pressure and a lack of cold Pacific air as key factors. These conditions trap heat near the surface, pushing up temperatures and creating the perfect environment for fog formation overnight.

But the big story is the approaching atmospheric river. This meteorological phenomenon draws moisture from the Pacific, funneling it into California in a narrow, concentrated band. When these systems arrive, they can deliver more rain in a few days than some regions see all month. For San Diego, it’s both a challenge and an opportunity: the rain can ease drought conditions, but also raises the risk of flooding and mudslides, especially in burn scar areas.

How Residents Are Responding

The record warmth has been a mixed blessing for locals. Outdoor enthusiasts have enjoyed sunny afternoons, while those hoping for traditional winter weather have been left wanting. Businesses along the coast and in the mountains report brisk activity, with hikers and beachgoers making the most of the mild conditions. However, fog and air travel delays have complicated holiday plans for many, underscoring the need for flexibility and vigilance.

With Christmas rain on the horizon, residents are preparing for a quick shift from sunshine to showers. Local authorities urge everyone to monitor weather updates, especially if traveling or participating in outdoor festivities. The unpredictable nature of atmospheric rivers means even a small change in the forecast could have a big impact.

Looking Ahead: What’s Next for San Diego?

San Diego’s December weather has offered a reminder of California’s meteorological variety. From record-breaking heat and foggy mornings to the prospect of a rain-soaked Christmas, the region’s climate continues to surprise. As always, the best advice is to stay informed and prepared—because in Southern California, the only constant is change.

For ongoing updates, residents are encouraged to follow local meteorologists like Megan Parry on social media and check with trusted outlets such as ABC 10News and NBC San Diego.

San Diego’s weather in December 2025 is a study in contrasts: summer-like warmth and persistent fog have upended expectations, but the looming atmospheric river promises a dramatic seasonal shift. The city’s ability to adapt—balancing outdoor life with preparedness for rain—remains key as residents navigate this remarkable stretch of weather.