On Monday, the torrid conditions set daily heat records across Southern California, including San Diego County. Oppressive highs of 118 degrees in Borrego Springs and of 106 degrees in Escondido each topped by 2 degrees previous records for June 20, set in 2008 and 1973, respectively. A 109-degree high in Ramona and of 110 degrees in Campo exceeded the previous records of 106 and 105, both set in 2008, and a 107-degree high in El Cajon was 13 degrees higher than the prior high, set nine years ago.
Records were also broken in Chula Vista with a high of 91 degrees, and tied in Alpine with a high of 107 degrees, according to the National Weather Service. Records were broken Sunday as well.
An excessive heat warning for the mountains and deserts is set to expire at 8 p.m. Wednesday.
In the forecast for Tuesday -- the second day of summer -- were highs of 73 to 78 degrees at the beaches, 80 to 85 degrees in inland coastal areas, 83 to 88 degrees in the western valleys, 90 to 95 degrees near the foothills, 92 to 100 degrees in the mountains and 111 to 116 degrees in the deserts.
Forecasters said high pressure slowly shifting to the east will ease the heat a little west of the mountains in San Diego County.
“High pressure aloft will gradually weaken today and Wednesday. As the onshore flow increases, the marine layer will slowly deepen this week and that will mean cooler weather west of the mountains,'' according to the weather service. “The weakening high and an increase in high clouds will also bring slightly cooler weather to the deserts today.''
Forecasters advised the public to avoid potentially serious heat-related ailments by staying well-hydrated, avoiding unnecessary outdoor labor and checking on neighbors and relatives -- especially those with health conditions and who lack air conditioning.
Authorities also warned against leaving children, seniors or pets in parked cars, which can quickly become death traps in high heat.