The National Weather Service kept a Severe Extreme Heat Warning in effect through 8:00 p.m. PDT on June 25 for the San Diego County deserts. The alert began the evening of June 23 and covered communities and travel corridors across the region, where prolonged sun and low humidity drove dangerous conditions. Last updated: 26 June 2026.
The warning mattered because dangerously hot days combined with warm nights can rapidly lead to heat-related illness. Limited overnight relief kept heat stress elevated, increasing risk for people working or recreating outdoors and those without reliable cooling. Gusty winds compounded hazards by affecting driving on exposed routes and posing a limited risk of localized power outages due to unsecured objects or tree limbs.
Warning window and affected area in San Diego County
The alert window ran from late June 23 until 8:00 p.m. PDT on June 25, underscoring a multi-day event rather than a brief spike. It covered the deserts of eastern San Diego County, including areas along exposed corridors and passes where terrain can amplify heat. Authorities advised residents and travelers in the desert zone to remain alert to changing conditions and to follow official guidance throughout the period, noting that cumulative exposure over consecutive days can heighten health risks for vulnerable groups.
Temperatures, winds and overnight conditions
Daytime highs reached approximately 106°F to near 110°F, pushing the upper range of early summer extremes for the area. Persistent heat was paired with gusty winds capable of blowing around unsecured objects and breaking tree limbs, potentially leading to localized service disruptions and making driving difficult for high-profile vehicles. Overnight lows in the 80s offered little relief, limiting the body’s ability to cool and compounding daytime strain, which can increase the likelihood of heat exhaustion and heat stroke, especially among the elderly, young children, and people with preexisting conditions.
Public guidance and services during the alert
Officials urged frequent hydration, limiting sun exposure, and using air-conditioned spaces to reduce heat load. Residents were reminded to check on neighbors and relatives who might be susceptible, and to never leave children or pets in vehicles under any circumstances. Drivers were advised to secure loose items, plan for wind-prone stretches, and adjust travel to avoid peak heat. Public cooling shelters may be available in some areas; residents were directed to consult county officials for locations and hours. Anyone experiencing symptoms of heat illness was instructed to move to a cool, shaded place, and to call 911 if conditions worsened.