95 was a real toaster. I reckon near 30'c
96 was a festival fallow year but I remember it being decent weather late june/july
99 & 2000 were good too, sunny but not as warm
97,98 & 2005 were wash out years.
My recent Glastonbury's haven't been too bad but it has rained a little at all of them since 2002 as far as I can remember