Oddly enough, I have found that a July 4th start date is generally spot on, regardless of the type of snow year that we have had. It is 90 degrees here today (I live about 2 miles from Waterton Canyon trail head, and really the first “hot” day we have had this year. So, you’ve got a full month until the 4th of July, and then you have a week or so on top of that to reach the higher altitudes on your hike. I’ve started many thruhikers, and myself, around this time, and it seems to be a consistently good target as a start date. FWIW.
TrailGuy