A strong upper level ridge settled over the region from October 23-25, 2017, before weakening slowly through the 27th. High pressure over the Great Basin brought weak to moderate Santa Winds that contributed dry air and compressional warming. Afternoon high temperatures over the coast and valleys soared past the century mark on the 23rd, 24th and 25th, breaking numerous records. Overnight temperatures in some wind prone spots failed to drop below 80 degrees. The San Diego Unified School District was hit hard, with 85 schools resorting to early releases on the 23rd, 24th, and 25th. The 108 degrees reported at Miramar Marine Air Station was the hottest temperature recorded so late in the year at any location other than RAWS sites. On October 24th, record highs and extremes occurred when Vista and Poway both peaked at 107, and 106 occurred at Oceanside Airport. Other readings included 105 at El Cajon and 105 at Huntington Beach, 106 at Fullerton and John Wayne Airports.

Excessive Heat in SAN DIEGO COUNTY COASTAL AREAS, CALIFORNIA
From 23-OCT-17 10:00:00 to 23-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Afternoon high temperatures ranged from the upper 80s at the coast to the low 100s inland. The ASOS stations at Miramar MCAS/Mitscher Field and Montgomery Field reached 103 and 102 degrees respectively. The San Diego Unified School District resorted to early releases at 85 schools with insufficient/no air conditioning.

Excessive Heat in SAN DIEGO COUNTY COASTAL AREAS, CALIFORNIA
From 24-OCT-17 10:00:00 to 24-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Afternoon high temperatures ranged from the mid 90s at the coast to the mid 100s inland. The ASOS stations at Miramar MCAS/Mitscher Field and Montgomery Field reached 107 and 106 degrees respectively. Vista was 105 degrees. The San Diego Unified School District resorted to early releases at 85 schools with insufficient/no air conditioning.

Excessive Heat in SAN DIEGO COUNTY COASTAL AREAS, CALIFORNIA
From 25-OCT-17 10:00:00 to 25-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Afternoon high temperatures ranged from the low 90s at the coast to the low 100s inland. The ASOS stations at Miramar MCAS/Mitscher Field and Montgomery Field reached 105 and 104 degrees respectively. The San Diego Unified School District resorted to early releases at 85 schools with insufficient/no air conditioning.

Excessive Heat in SAN DIEGO COUNTY VALLEYS, CALIFORNIA
From 23-OCT-17 10:00:00 to 23-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

High temperatures ranged from the upper 90s to low 100s across the valleys. A peak of 107 degrees occurred in Fallbrook. El Cajon set a daily record with a high of 104 degrees, the 4th warmest October day on record.

Excessive Heat in SAN DIEGO COUNTY VALLEYS, CALIFORNIA
From 24-OCT-17 10:00:00 to 24-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Afternoon high temperatures soared into the upper 90s and 100s, with a peak value of 110 degrees reported by a mesonet station in Poway. El Cajon recorded the cities 2nd warmest October day on record at 105 degrees.

Excessive Heat in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 23-OCT-17 10:00:00 to 23-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Highs in the Inland Empire were in the upper 90s and mid 100s. Chino Airport reached 106 degrees and a mesonet in Montclair was 107 degrees.

Excessive Heat in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 24-OCT-17 10:00:00 to 24-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

High temperatures were in the upper 90s and 100s for the second day in a row. Montclair was 106 degrees.

Excessive Heat in ORANGE COUNTY INLAND, CALIFORNIA
From 23-OCT-17 10:00:00 to 23-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Temperatures spiked significantly with afternoon highs topping out in the 100-110 degree range. A station in Rancho Santa Margarita reported a high of 110 degrees.

Excessive Heat in ORANGE COUNTY INLAND, CALIFORNIA
From 24-OCT-17 10:00:00 to 24-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Afternoon high temperatures were extreme for a 2nd day in a row, anywhere from 100-111 degrees. The peak value of 111 degrees occurred in Laguna Niguel.

Heat in ORANGE COUNTY INLAND, CALIFORNIA
From 25-OCT-17 10:00:00 to 25-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Temperatures peaked in the upper 90s and low 100s. A mesonet in Fullerton was 104 degrees.

Heat in SAN DIEGO COUNTY VALLEYS, CALIFORNIA
From 25-OCT-17 10:00:00 to 25-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Valley highs were in the upper 90s and low 100s, with a peak of 104 degrees recorded in Pala. El Cajon and Escondido set daily records with readings of 102 and 100 degrees respectively.

Excessive Heat in ORANGE COUNTY COASTAL, CALIFORNIA
From 23-OCT-17 10:00:00 to 23-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Afternoon highs ranged from the upper 80s to upper 90s. Isolated areas several miles inland recorded values into the 100s, including 108 degrees at the Cattle Crest Trailhead mesonet station.

Excessive Heat in ORANGE COUNTY COASTAL, CALIFORNIA
From 24-OCT-17 10:00:00 to 24-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Afternoon highs at the beaches were in the mid 90s, while locations just a couple miles inland soared into the 100s. The highest value was at Cattle Crest Trailhead, with a high of 109 degrees. John Wayne Airport was 106 degrees, and Santa Ana was 104 degrees (tied for the 4th warmest October day on record).

Excessive Heat in ORANGE COUNTY COASTAL, CALIFORNIA
From 25-OCT-17 10:00:00 to 25-OCT-17 17:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Highs in most areas were in the mid 90s. A peak value of 103 degrees occurred at Cattle Crest Trailhead. A reading of 102 degrees was also reported at Lower Moro Campground.