Hi SamHobbs,
Crepe Myrtles (Lagerstroemia) love heat so I don't think the 100ยบ temp's have anything to do with lack of blooms but I guess it could possibly be due to other weather conditions like possibly not enough moisture. I wonder if perhaps they were in bloom earlier last year (right after planting) because they were greenhouse grown with higher humidity levels? Once established, they are drought tolerant but they love high humidity. They may just be slow in setting blooms for some reason this year; I've seen that happen even here in Florida at times but I have no clue why they would bloom earlier some years than others. Maybe those trees will surprise you and pop into full, glorious bloom in the next few weeks.
