Areas across Arizona are so hot that cactus are dying, food is baking and plastic is melting.
"Arizona has had record or near-record heat for over a week now," AccuWeather Senior Meteorologist Ken Clark said.
While the heat will ease this week, temperatures will remain higher than normal, Clark added.
On June 20, 2017, Phoenix hit a new daily heat record at 119 degrees Fahrenheit, surpassing the previous record of 116 F.
A high fire danger is in place due to the blistering heat and occasional wind, according to Clark.
The fire danger will remain high in Arizona this week as the area will remain rain-free.
The National Weather Service has issued an "excessive heat warning", effective until Sunday evening local time, for south-central and southwest Arizona.
As far north as San Francisco, residents were advised to avoid strenuous activities in the heat, if possible, and don't leave kids or pets in vehicles.
Temperatures in Las Vegas hit 117 degrees this afternoon.
Lows will only fall into the mid-80s early mornings.
In addition to power outages, wildfires, general misery and health risks, the temperatures - which reached 119 degrees Fahrenheit on Tuesday in Phoenix - are leading to flight cancellations.
On average, Phoenix temperatures for this time of year are generally between 105 and 110 degrees. American Airlines canceled 20 regional flights out of Phoenix Sky Harbor International Airport on Tuesday after temperatures in the desert city soared toward 120 degrees F (49 C).
Forecasters also warned Phoenix could hit 120F (48.8C) degrees this week.
American Airlines said in a statement that the Bombardier CRJ aircraft used on some shorter routes have a maximum operating temperature of 118 degrees.
Larger jets, such as those manufactured by Airbus AIR, -0.59% and Boeing BA, -0.38%, aren't expected to be affected by this week's heat.
Unfortunately, most runways aren't long enough to accommodate the extra distance the planes would need to reach that speed.
And pilot Patrick Smith says the plane's brakes and machinery can overheat.
Denver International Airport, for example, is already at a higher elevation than most USA airports.
At that point, "things begin to break down", he said.
"People can go right from what they think is heat exhaustion to symptoms of a heat stroke which is actually a fatal illness", said Phoenix Fire Department Captain Reda Bigler.
Dozens of flights were cancelled Tuesday in Phoenix as extreme heat swept over the region, prompting officials to deem it too hot for some planes to fly.
As air temperature rises, the density of the air decreases - making the air thinner.
Temperatures were expected to drop by five to 10 degrees later in the week, the NWS said.
Expect to see more of the same over the coming years and decades, as rising temperatures bring down quite a number of the services and infrastructure that modern industrial society depends upon.