Most of the Inland Empire will feel triple-digit temperatures over Labor Day weekend, prompting the National Weather Service to issue a heat advisory for the three-day period.
The advisory is in effect through 8 p.m. Monday, covering all of the valleys in Riverside and San Bernardino counties. Temperatures at higher elevations are forecast to be milder but still unseasonably warm.
“Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun,” an NWS statement advised. “Take extra precautions if you work or spend time outside. When possible, reschedule strenuous activities to early morning or evening.”
Saturday’s highs were expected to reach 109 degrees in Palm Springs, 102 in Lake Elsinore, 101 in Riverside, 99 in Hemet and 84 in Idyllwild, according to the NWS.
Forecasters said the hottest day of the long weekend will be Sunday, which will see highs up to 10 degrees above average, with Palm Springs expected to hit 112 and Riverside 105. Although a few degrees will be knocked off those temperatures by Monday, many places around the Inland Empire will still see the mercury surpass the century mark on Labor Day.
Overnight lows throughout the weekend will be in the low 70s in the Riverside metropolitan area and in the 80s in the Coachella Valley, according to the NWS.
Meteorologists said a ridge of high pressure building over Central California will dominate the region, reducing relative humidity and creating bone-dry conditions.
“With the heat building in, combined with dry fuels and diurnal winds, a few hours of elevated fire weather conditions are possible for inland areas each afternoon this weekend and early next week,” the NWS stated.
The ridge will cede to lower pressure systems going into Tuesday, drawing moisture from the coasts and returning temperatures to more seasonable levels, forecasters said.