i am teacher/ coach so june is our only real option.
we have been in june 5 times.
the weather is hot, but not sweltering, especially in morning or night. rain is hit and miss. we have been some years and only seen one shower in 5 days and then last year saw some rain most days and a lot of rain two of the days.
tips,
the earlier in june the better, usually good park hours and fewer people.
hit early entry to beat some of the heat.
if time, take a break after lunch back at the resort, kids and adults can get cool, swim, take a nap and get reenergized for the afternoon and night.
space out your attractions if possible to give yourself some time in the cool waiting for the ride. (like do space mountain after buzz because most of wait is inside where buzz is mainly outside waiting therefore hotter)
just let me know if you need any other info.
mikewdw