:. Phoenix August Weather .:

The Phoenix temperature starts to drop a few degrees in August, but Phoenix August Weather still resembles July with higher humidity and an increased chance of thunderstorms. However, Phoenix is in the Desert Southwest, not Florida. The Phoenix humidity is still pretty low, and the chance of rain in Vegas is remote. August weather is usually comfortable early in the morning, and if you get too warm or you get thirsty you can always walk inside the casinos or the large Vegas Strip shopping centers. August weather in Vegas is something you need to plan for, but it's usually not so hot that you should avoid it.