In Arizona, known as The Valley of the Sun, temperatures can regularly top 100′. The higher temps in Phoenix & Scottsdales are going to signal the onset of monsoon season storms. Heatwaves are a triggering mechanism that starts the thunderstorms that will turn into monsoons over the summer rainy seasonar.
While monsoon season raises the average humidity levels, the rain cool the region. While the monsoon rains typically arrive after July first, the moisture drawing into the state now is indicative of the summer storm season looming on the horizon.
Hot temperatures cause the formation of low pressure ridges which draw moisture from the Gulf of California and the Pacific Ocean. This then can become a deluge during the Arizona monsoon season. Phoenix and Scottsdale have seen exceptionally high temperatures this spring including a high of 118 degrees (the fifth-hottest day ever recorded in Phoenix). The extreme weather will continue through the summer monsoon season and excessive heat warnings will be common.
During the high heat and monsoon rains you should to stay indoors and out of the weather. The hottest parts of the day can be draining, and be sure to drink plenty of water to stay hydrated.