hi there,
Summer is very hot, but it's best time to be there if you want to enjoy amusement and water parks, Frontier City and so on.
Spring and Autumn is also great in terms of
weather and it's not as hot but the weather is warm and you can enjoy things like hiking, fishing, etc.
For instance, the blooming Myriad Botanical Gardens in spring is a lovely
attraction worth visiting.
Hope this helps
Vacationbuddy