Mid-90s daytime high temperatures were expected on Monday, before seeing the mercury ramp back to, or above, the 100-degree mark beginning on Tuesday.
An excessive heat warning is in effect for the Coachella Valley and the San Gorgonio Pass zone, which includes the cities of Banning and Desert Hot Springs, will remain in until 9 p.m. Wednesday.
The heat will be on "high" in the Desert Southwest the next several days. Keep in mind to check pavement temperatures by feeling it with the back of your hand - if it's hot for you, it's too hot for your pet to walk on.
An excessive heat warning is in effect for Oklahoma County through 9 p.m. Saturday, according to the National Weather Service.
Residents are encouraged to take precautions these coming days, especially by people who participate in outdoor activities, older adults, caretakers of infants and children and those sensitive to heat, county officials said in a news release.
The Phoenix forecast office says all-time high temperature records could fall. Heat stress possible for livestock with limited relief from the heat overnight.
The hot conditions are labeled as a classic pre-monsoon heat event for the Southwest region, NWS said.
In Las Vegas, temperatures are forecast to be 110 degrees or hotter this weekend through next week.
The hot weather will increase the risk of heat-related illness and anyone working or spending time outdoors would be more susceptible, as will senior citizens, children and those unaccustomed to the heat.
Inland cities in the East and North Bay are expected to hit 90-100 degrees, and "southern Salinas Valley and Pinnacles National Park are both expected to exceed 100 degrees", BCN reports.
In California, triple-digit heat will engulf Bakersfield, Fresno and Sacramento starting this weekend and continuing into next week.