The news prompted the operator of California's electrical grid to call for voluntary conservation of power Tuesday and Wednesday due to high temperatures in much of the West.
Parts of Utah were also issued an excessive heat warning with temperatures this week expected to approach 109 degrees (43 Celsius).
The National Weather Service said southern Arizona will experience temperatures from 112 to 119 degrees (44 to 48 Celsius) through July 25.
An Excessive Heat Warning has been issued for the county starting on Monday at 10 am through Thursday at 8 pm.
The weather service said other record highs set Tuesday included 122 (50 Celsius) in Thermal, in California's Coachella Valley, and 121 (49.4 Celsius) in Palm Springs.
"The hottest weather of the year will persist the next several days with near record highs for many locations", the National Weather Service in Phoenix said.
The weather agency uses a complicated formula that varies from region to region to declare an excessive heat warning, including close to record-breaking temperatures. By mid-week, monsoonal moisture will move back into the area and drop temperatures.
The NWS issued a High Surf Advisory beginning Monday at 8 a.m. and lasting through 9 p.m. Wednesday.
Austin Public Health and Williamson County and Cities Health District additionally stated to never leave children and pets in vehicles for any period of time.
"When temperatures are high, even a few hours of exertion may cause severe dehydration, heat cramps, heat exhaustion and heat stroke".
In addition, young children and pets should never be left unattended in vehicles during hot weather, when auto interiors can reach lethal temperatures in a matter of minutes, officials warn.
Valley temperatures could reach 115 on Monday, according to National Weather Service meteorologist Larry Hopper.
High surf warnings will also be in effect as people make their way to the beach to cool off.
"Nationwide, heat is the #1 heat-related killer", the weather service in Phoenix said on its website.
Maricopa County public health officials say 155 people died in the Phoenix area previous year from heat-caused illnesses such heat stroke.
"Late in June the numbers really started peaking and we haven't seen it let off really since 4th of July", said San Diego Lifeguard Lt. John Sandmeyer.
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