More than 80 million Americans are currently under dangerous heat advisories. Temperatures in California's Death Valley hover around 120 degrees Fahrenheit at midnight. Phoenix as of July 31 had seen 31 straight days of heat over 110 F, the cause of 25 deaths. Spain, Greece and Italy have recorded all-time high temperatures. In several Middle Eastern countries, the heat index mid-July reached 152 F, considered almost at the limit for human survival.