Arizona Public Service Company, the largest electricity provider in Arizona, said temperatures near 120 degrees in Phoenix led customers to set a new peak usage record.
According to the Arizona Republic, the heat in Phoenix had so far affected American Eagle regional flights between 3 p.m. and 6 p.m. on Tuesday at Sky Harbor International Airport. "We really aren't expecting any change to the operation with our mainline aircraft".
Death Valley, California, reached 127 Tuesday and Palm Springs hit 122, tying the degree for the same day a year ago.
The high heat, which the National Weather Service has warned about since last week, stretches into parts of California.
Temperatures on Tuesday were expected to reach 49 degrees Celsius, which is too hot for some planes to operate.
Arizona is seeing some of the most dramatic temperatures Tuesday, but the heat wave is being felt across Nevada and California, too. Phoenix will also be within reach of tying the record for consecutive days of high temperatures greater than 115 degrees, which is four days set in 1990.
The western United States is reporting record-breaking temperature highs and the heat wave is messing with people's plans left and right.
Major airlines delayed and cancelled flights out of Las Vegas and Phoenix airports as temperatures hit the high 40s, citing difficulty in operating aircraft in extreme heat - causing plenty of headaches for airlines and travellers alike.
The reason it can get so hot in the Southwest is that the humidity is so low. A Tuesday afternoon update said that although the official forecast high in Phoenix was 120 degrees, debris clouds and a bump up in humidity could result in a slightly cooler observed high.
In Phoenix, temperatures around 118 are infrequent enough that airlines continue to use regional jets for shorter trips.
Steve Smith wipes sweat from his face as temperatures climb to near-record highs in Phoenix on Monday, June 19, 2017. The study of almost 2,000 deadly heat waves worldwide since 1980 was published Monday in the journal Nature Climate Change.
The forecast calls for 119 degrees in Phoenix, where some flights have been cancelled because certain planes can't take off in extreme heat.
Phoenix authorities issued several warnings about the dangers of the heat.
Dr. Kevin Foster warned people to be extra careful around concrete, vehicle interiors and playground equipment, especially young children who have sensitive skin.
They said on Twitter that it's "like your skin and flesh are burning off".
Extreme heat made the fight against wildfires burning in the Southwest more hard Wednesday, the Associated Press reports. All flights were canceled on that day because the runway at Sky Harbor was made from asphalt, and it became soft and started to melt.