Important news, but they gotta start proofreading their articles better:
The city of Phoenix, which has been experiencing temperatures above 109.4F (43C) for 17 days in a row, was granted some modest reprieve on Sunday by a thick cloud cover, which was expected to keep the temperature around 115F (46.1C).
I'm not seeing how an increase from 109 to 115 degrees is a reprieve.
I think it's just a weird wording, but not factually wrong. I read that as it would of been higher than 115F but thick cloud cover helped to keep it at that lower temperature.