And it was so hot that dozens of flights have been canceled this week at Phoenix Sky Harbor International Airport. American Airlines alerted its customers over the weekend, offering fee-free changes to upcoming flights that were departing or arriving at Phoenix between 3 and 6 p.m., when temperatures peak. https://www.washingtonpost.com/news/capital-weather-gang/wp/2017/06/20/its-so-hot-in-phoenix-that-airplanes-cant-fly/