At 2:45 a.m. today, offshore winds blowing at Diablo Canyon nuclear power plant produced a temperature of 92 degrees, reports local weather forecaster John Lindsey.
Lindsey said another weather watcher that he uses for data gathering reported a temperature of 88 degrees in Shell Beach at 3:45 a.m.
Offshore winds compress as they race toward the coast, and that is what causes such unusual heating.
Today’s high temperatures will likely break records for the date, said Lindsey. He expects a high in San Luis Obispo this afternoon of 106 degrees. The previous record for this date is 104 degrees, set at Cal Poly in 1993.
The record of 105 degrees in Paso Robles will likely be broken as well, as Lindsey expects that city to reach 107 degrees today.
Even the northwest-facing beaches, typically the coolest spots in the county, will be part of the heat wave. Lindsey said Los Osos, Morro Bay and Cambria will see readings in the 90s.
Another hot day, though somewhat cooler, is expected Tuesday. The high pressure responsible for the heat wave will relent by Wednesday, Lindsey said, as onshore winds bring back fog and more seasonal temperatures.