Phoenix shatters heat record that has stood for almost 50 yearsThe Valley of the Sun set a new record for the longest stretch of temperatures at that extreme threshold, and one AccuWeather expert explains that record could be broken again — many times. For the past 19 days, Phoenix has sweltered under temperatures at or above 110 degrees Fahrenheit amid an unrelenting heat wave, shattering a record that has stood for nearly 50 years. The old record streak of 110-degree days was set from June 12-29, 1974. The streak isn’t likely to end Tuesday, however, with AccuWeather forecasters saying the heat will do more than just shatter the record. Even with the streak in Phoenix forecast to come to an end late next week, temperatures aren't likely to bring relief.