Summer doesn't technically arrive until June 21, but forecasters on Monday are already warning about triple-digit temperatures that, mixed with low humidities and gusty winds, could ignite brush fires across Southern California.
Inland areas can expect highs up to 90 to 100 degrees Fahrenheit through Tuesday, while temperatures in coastal communities can reach 70 to 80 degrees Fahrenheit.
Forecaster said that heat, combined with very low humidities and Santa Ana winds gusting northeast-east with speeds of up 20 to 30 mph during the morning hours, means elevated fire danger--especially in the interior regions.
In Hesperia, crews were already battling a 3 to 4-acre vegetation fire in the 13700 block of Mojave Street on Monday morning, the San Bernardino County Fire District said just after 9:30 a.m. Flames were spreading at a moderate speed, but they weren't threatening any structures, authorities said.
Fontana, the Hollywood Hills, Castaic and Santa Clarita all saw brush fires on Sunday, when conditions were similarly hot, dry and windy.
"[The] first heat of the summer means the conditions may be especially impactful," the National Weather Service cautioned.
The agency advised the public to watch out for potential heat-related health issues. Babies, outdoor workers, the elderly and people who are homeless are especially vulnerable, the Weather Service noted.
"Remember your hot weather tip and take extra precautions during this time," the Weather Service said.