Live in the Palm Springs area, where it has been 100-115 degrees most every day. I am presuming that one should not apply Elastomeric (over previous Elastomeric on Stucco) in this heat. Is this correct? If so, what is the maximum temperature allowable for this application?
High temperatures are a problem when applying any coating. Generally, the best temps are under 90 degrees with 50% or less humidity. But, this isn't always possible.
High temperatures will cause the coating to dry too fast, making it difficult to have a uniform looking finish.
A way to combat the high temperatures is to work in the shade, follow the sun. Also, apply the elastomeric paint early in the morning when it is cooler. Thinning with water can also help by slowing down the drying, but to much thinning will damage the coating or force you to apply 2 coats.
If you can, wait until the fall when it will be cooler. Cooler temps will be better for you and the elastomeric paint.