Like the majority of the responses, it is very hot and very energy sucking humid still in September. We only went once during thst month and it was our last time. Later in October or November are better. November is our favorite time to go.
it is incredibly hot. in fact, we visited once in September and I swore never again. we started going in April and its our month of choice now. its always pretty warm there but its more bearable during the winter months and early spring. good luck!