Excessive Heat in Riverside County Mountains, California

A long-duration, excessive heat wave occurred across the Riverside County Mountains from July 14-22. Highs reached the upper-80s and 90s each day, with a few days topping 100 degrees. The following are the highest temperatures reported during the event, and the day on which the peak temperature occurred:

Idyllwild: 100 (7/15/23) Idyllwild ranged from 90-100 through the duration of the event, with overnight lows of 58-66 degrees each day. Idyllwild broke a high temperature record at 100 (7/15), breaking the old record of 97.

Anza: 104 (7/15/23) Anza ranged from 95-104 through the duration of the event, with overnight lows of 59-69 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.