San Diego County, December 11, 2025
San Diego County is currently experiencing an unprecedented heatwave, with temperatures significantly surpassing average mid-December levels. Chula Vista reached a high of 84°F, while Ramona had 88°F, both setting records for this time of year. Factors such as high-pressure systems and weak Santa Ana winds have contributed to the abnormal heat, posing challenges for residents and local infrastructure. As temperatures are expected to stay elevated, preparedness measures from past extreme events are being highlighted.
San Diego County Experiences Record-Breaking Heat
San Diego County has recently been in the grip of a heatwave that shattered temperature records, demonstrating the region’s vulnerability to extreme weather. On December 9, 2025, Chula Vista reached a remarkable 84°F, clinching a daily record, while Escondido matched its highest with a temperature of 86°F. The following day brought further heat as Chula Vista maintained its record and Ramona topped out at 88°F—both figures approximately 15 degrees above typical mid-December averages.
This unusual heat phenomenon is primarily attributed to high-pressure systems coupled with weak Santa Ana winds. These factors have driven temperatures upward while substantially lowering humidity levels. According to forecasts from the National Weather Service, while a slight dip in temperatures is expected over the weekend, figures will likely remain elevated by as much as 15 degrees above the norm. Coastal areas may see highs in the mid-60s to low-70s, inland regions in the mid-70s, alpine areas in the mid-60s, and deserts reaching up to the upper 70s. Additionally, weaker offshore winds are anticipated through Thursday, maintaining dry conditions across the region.
Details of the Heatwave
The current heatwave is a stark reminder of the extreme weather patterns San Diego County can encounter, posing challenges for residents and businesses alike. In the past, the city has enacted measures to combat similar events, such as activating “Cool Zones” in August 2025, which provided much-needed air-conditioned spaces for the public. Extreme weather like this underscores the importance of community preparedness and innovation to navigate changing climate patterns.
Historical Context
San Diego County’s historical context concerning weather extremes illustrates both challenges and resilience. The activation of “Cool Zones” in response to summer heat reflects local authorities’ commitment to public health and safety. Moreover, the January 2024 rainstorm that led to significant flooding emphasized the need for ongoing attention to infrastructure and emergency preparedness. Such occurrences serve as vital learning experiences, fostering a community that is better equipped to deal with irregular climate activity.
Frequently Asked Questions (FAQ)
What temperatures were recorded in San Diego County on December 9 and 10, 2025?
On December 9, 2025, Chula Vista recorded a high of 84°F, setting a new daily record, while Escondido tied its record with a high of 86°F. On December 10, 2025, Chula Vista maintained the 84°F high, and Ramona reached 88°F, surpassing its previous record. These temperatures are approximately 15 degrees above the typical mid-December averages for the region.
What factors contributed to the recent heatwave in San Diego County?
The heatwave is attributed to a combination of high-pressure systems and weak Santa Ana winds, which have been pushing temperatures higher and reducing humidity levels.
How long is the current heatwave expected to last?
The National Weather Service forecasts that while temperatures may decrease slightly by the weekend, they will remain up to 15 degrees above average. Coastal areas can expect highs in the mid-60s to low-70s, inland areas in the mid-70s, mountains in the mid-60s, and deserts in the upper 70s. Winds are expected to be weakly offshore through Thursday, continuing the very dry conditions. The marine layer is anticipated to return Thursday evening into Friday morning, bringing patchy dense fog, especially near the coast, which may impact the Friday morning commute with low clouds and fog spreading farther inland into the weekend.
Has San Diego County experienced similar extreme heat events in the past?
Yes, San Diego County has a history of experiencing extreme heat events. For instance, in August 2025, the city activated its “Cool Zones,” providing air-conditioned spaces for residents to escape the heat. Additionally, in January 2024, a historic rainstorm brought 2.73 inches of rain in a 24-hour period, causing significant flooding in several neighborhoods. These events highlight the region’s vulnerability to extreme weather conditions and the importance of preparedness.
Key Features of the Recent Heatwave in San Diego County
| Feature | Details |
|---|---|
| Record Temperatures | Chula Vista reached 84°F on December 9, 2025; Ramona reached 88°F on December 10, 2025. |
| Contributing Factors | High-pressure systems and weak Santa Ana winds leading to higher temperatures and reduced humidity. |
| Duration | Temperatures expected to remain up to 15 degrees above average through the weekend. |
| Historical Context | San Diego County has experienced similar extreme heat events, such as the activation of “Cool Zones” in August 2025 and a historic rainstorm in January 2024. |
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Author: STAFF HERE SAN DIEGO WRITER
The SAN DIEGO STAFF WRITER represents the experienced team at HERESanDiego.com, your go-to source for actionable local news and information in San Diego, San Diego County, and beyond. Specializing in "news you can use," we cover essential topics like product reviews for personal and business needs, local business directories, politics, real estate trends, neighborhood insights, and state news affecting the area—with deep expertise drawn from years of dedicated reporting and strong community input, including local press releases and business updates. We deliver top reporting on high-value events such as Comic-Con International, San Diego County Fair, and San Diego Pride Festival. Our coverage extends to key organizations like the San Diego Regional Chamber of Commerce and United Way of San Diego County, plus leading businesses in biotechnology, healthcare, and technology that power the local economy such as Qualcomm, Illumina, and Scripps Health. As part of the broader HERE network, including HEREAnaheim.com, HEREBeverlyHills.com, HERECostaMesa.com, HERECoronado.com, HEREHollywood.com, HEREHuntingtonBeach.com, HERELongBeach.com, HERELosAngeles.com, HEREMissionViejo.com, and HERESantaAna.com, we provide comprehensive, credible insights into California's dynamic landscape.
