Climbed East Arete on July 25 with my 14 y/o son (his first time being on the snow or climbing on class 3 in the Sierra). We camped at 10700' on the bench above the lake and the JMT heading up the Donahue Pass. Some mosquitoes, but not too much to worry (scale 4 of 10). A lot of streams and snow melting.
Continous snow from ~11500 with snow cups. The glacier is with heavy water runs on the surface which makes traveling along the sun-cupped channels OK, but traversing them tiring. Snow was soft, the night temps above freezing. Did not use the crampons and kept to the left along the rigde that cuts the Lyell Glacier.
The rock on the arete is solid granit. I kept on the crest with some class 4 moves.
We met fellow SPers (Vitaly M, Maxim and Chad) who were doing Lyell and McCluer.