High pressure at middle and upper levels of the atmosphere led to another round of weak Santa Ana Winds across portions of Southern California. The primary impact from the Santa Anas was hot daytime temperatures, with multiple daily records set during this event.

Heat in ORANGE COUNTY INLAND, CALIFORNIA
From 18-OCT-23 12:00:00 to 20-OCT-23 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

High temperatures across inland portions of Orange County on October 18th through the 20th were notably hotter than seasonal normal. Highs were routinely in the upper 80s to upper 90s during this time. The hottest day was October 20th when Anaheim hit 97 degrees for a high, Yorba Linda hit 95, while Fullerton hit 92.

Heat in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 18-OCT-23 12:00:00 to 20-OCT-23 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

High temperatures across the Inland Empire on October 18th through the 20th were notably hotter than seasonal normal. Highs were routinely in the lower 90s to just over 100 degrees during this time. The hottest day was October 18th when Riverside Airport hit 102 degrees for a high, Ontario hit 101, and San Bernardino Airport hit 100.

Heat in SAN DIEGO COUNTY VALLEYS, CALIFORNIA
From 18-OCT-23 12:00:00 to 20-OCT-23 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

High temperatures across the San Diego County Valleys on October 18th through the 20th were notably hotter than seasonal normal. Highs were routinely in the upper 80s to upper 90s during this time. The hottest day was October 20th when San Pasqual Valley hit 99 degrees for a high, Ramona hit 97 degrees, and Escondido hit 95.

Heat in SANTA ANA MOUNTAINS AND FOOTHILLS, CALIFORNIA
From 18-OCT-23 12:00:00 to 20-OCT-23 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

High temperatures across portions of the Santa Ana Mountains on October 18th through the 20th were notably hotter than seasonal normal. Highs were routinely in the upper 80s to upper 90s during this time. El Cariso hit 97 degrees for a high temperature on both the 19th and 20th of October.

Heat in SAN DIEGO COUNTY MOUNTAINS, CALIFORNIA
From 18-OCT-23 12:00:00 to 20-OCT-23 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

High temperatures across portions of the San Diego County Mountains at elevations generally below 5000ft on October 18th through the 20th were notably hotter than seasonal normal. Highs were routinely in the upper 80s to upper 90s during this time.  Campo hit 98 degrees for a high on both the 19th and 20th, while Alpine hit 95 degrees and Julian topped out at 87 degrees on the 19th.

Heat in SAN DIEGO COUNTY DESERTS, CALIFORNIA
From 18-OCT-23 12:00:00 to 20-OCT-23 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

High temperatures across portions of the San Diego County Deserts on October 18th through the 20th were notably hotter than seasonal normal. Highs at Borrego Springs ranged from 99 to 104 degrees during this time.

Heat in COACHELLA VALLEY, CALIFORNIA
From 18-OCT-23 12:00:00 to 20-OCT-23 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

High temperatures across portions of the Coachella Valley on October 18th through the 20th were notably hotter than seasonal normal. Highs at Palm Springs International Airport ranged from 104 to 108 during this time, while Thermal Airport's highs ranged from 102 to 105.