Excessive Heat in San Diego County Valleys, California

A long-duration, excessive heat wave occurred across the San Diego County Valleys from July 11-22. Highs reached the upper-80s and 90s each day, with a few locations topping 100 degrees. The following are the highest temperatures reported during the event, and the day on which the peak temperature occurred:

Ramona AP: 100 (7/20/23) Ramona AP ranged from 93-100 through the duration of the event, with overnight lows of 58-67 degrees each day.

Santee: 100 (7/17/23) Santee ranged from 87-100 through the duration of the event, with overnight lows of 62-68 degrees each day.

San Pasqual Valley: 100 (7/17/23) San Pasqual Valley ranged from 90-100 through the duration of the event, with overnight lows of 56-66 degrees each day.

Valley Center: 100 (7/17/23) Valley Center ranged from 93-100 through the duration of the event, with overnight lows of 60-69 degrees each day.

Rancho Bernardo: 90 (7/15/23) Rancho Bernardo ranged from 81-90 through the duration of the event, with overnight lows of 63-66 degrees each day.

Alpine: 98 (7/17/23) Alpine ranged from 89-98 through the duration of the event, with overnight lows of 62-72 degrees each day.

A long duration heat wave impacted inland portions of Southern California July 7 to 29 with nearly continuous warnings and advisories. San Diego County public health reported 224 heat related incidents around their network of 23 hospitals. Numerous record highs were broken in the lower deserts where temperatures topped 115 for many days in a row, as well as across the inland valleys and mountains. Overnight low temperatures remained elevated in the lower deserts as lows only fell into the mid-80s to mid-90s, exacerbating the extreme heat risk.

July 2023 was the hottest month on record at Palm Springs.