The unseasonably hot weather in the first week of spring drove the mercury to record-breaking levels Monday in Idyllwild and San Jacinto, according to the National Weather Service.
The agency said the daytime high in the mountaintop community of Idyllwild reached 84, topping the prior record for the date of 76 established in 2025.
In San Jacinto, the temperature peaked at 92 on Monday, erasing the previous record of 86 set in 1986, the NWS said.
There were no other reportable records set in Riverside County on Monday.
However, the summer-like swelter was forecast to continue all week as high pressure patterns continue to influence the regional climate, according to the weather service.
“Daytime high temperatures will range from around 10 degrees above average near the coast, to 15 to 20 degrees above average for inland areas,” the NWS stated. “Daily maximum records may be broken or tied in the inland areas.”
Over four consecutive days last week, multiple locations across the Inland Empire set temperature records, most of them because of triple-digit heat.
For the remainder of the week, highs in the Riverside metropolitan area were forecast to climb into the low 90s, dropping to the low 60s overnight. The Temecula Valley was also expected to peak in the low 90s by day, and drop to the mid-50s at night.
The Coachella Valley’s highs will top out in the low 100s going into the weekend, settling in the upper 60s during the overnight hours.
“For the weekend into early next week, temperatures will trend lower and marine layer clouds and fog will spread farther inland as the high pressure ridge weakens and gets displaced to the southeast, as a low pressure trough approaches the coast from the west,” according to the NWS.