Phoenix has relentlessly baked for months. In July, it clinched its hottest month on record. Then August topped that and became the new hottest month. The back-to-back records propelled the country’s sixth-largest city to its hottest summer (June through August) on record by a wide margin. The summer finished 1.6 degrees above the previous high mark. The scorching heat in Phoenix and other parts of the desert Southwest comes as several other parts of the Lower 48 also registered their hottest summers.

Phoenix feeling like fire

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The heat milestones established in Phoenix during the summer are too many to list. “By essentially any metric, this has been the city’s hottest summer on record,” Paul Iñiguez, science and operations officer at the National Weather Service office in Phoenix, wrote in an email.

  • Hottest August and hottest month: August’s average temperature of 99.1 degrees, 0.8 degrees above the previous hottest August, represents the hottest month on record in Phoenix. The blistering average high of 110.7 is the hottest of any month as well. In addition, the 12 nights with low temperatures at or above 90 best the previous August record of eight such nights, set in 2011, for a new August record.
  • Hottest July and second-hottest month: The average temperature of 98.9 degrees sets a July record, boosted by an average high temperature of 109.8 degrees. With 16 instances of nighttime lows 90 degrees or greater, the most of any month, there was little relief.
  • Hottest summer: The summer started inauspiciously, with the average June temperature of 92 degrees ranking as the 21st hottest on record. Then came the back-to-back furnace-like conditions in July and August. The summer average temperature of 96.7 degrees demolishes the old summer mark of 95.1 degrees set in 2015 and 2013.
  • Most 90-degree nights: The temperature never dropped below 90 on 28 nights. The old record was 15 such instances, set in 2013 and 2003. There were two separate week-long streaks of nights not falling below 90.
  • Most 110-degree days: The 50 days with high temperatures at or above 110 degrees destroys the old record of 33 such days in 2011. In July and August, 66 percent of days were at or above that mark, with roughly a dozen high temperature records set in the process.
  • More excessive heat warnings: The Weather Service issued these warnings, the most severe heat alert, 43 times, vastly outpacing other years in the past decade-plus.