When travelling, it's generally smart to pack in preparation for rain or any other conditions that may arise. The rainfall in Saskatoon is roughly greater than that of Yuma. You can assume this to be the case over the next 19 days.
Temperatures around the 42 °C's can be experienced in July. The weather in Yuma is hotter than in Saskatoon. Plan for potential changes in flight availability as peak weather approaches in this location.