Even by Arizona standards, it was blistering heat. The National Weather Service said the four-day stretch, averaging 103.7 degrees between Thursday and Sunday, was the warmest on record for August.

And it wasn't just the daytime highs. It was the nighttime lows that set records as well, with temperatures never falling below 93 during that stretch. 

State climatologist Dr. Nancy Selover said it’s because dew point temperatures were also higher than normal.

“We’ve been having this additional humidity and it just takes the energy right out of you because you sweat and then nothing happens, the sweat just sits there on your skin and you don’t get any cooling relief whatsoever," Selover said. "It’s just very difficult when the night goes by and you only get down to 93 degrees.”

Selover said higher-than-normal humidity made for a double whammy of warmth.

“Part of why that daytime was so uncomfortable is (because) we’ve had dew point temperatures in the mid to upper 50s," Selover said. "Combined with these really high temperatures, that makes it really unbearable, but then that moisture at night is what’s been helping to keep those nighttime temperatures so high.”

So far this year, according to the Weather Service, Arizona has had 19 days with temperatures of 110 degrees or above, already surpassing the yearly average of 18.