Hey Alex,
www.postholer.com has very good PCT snowpack info.
Also,the desert sections in SoCal are sporadic – you are in & out of the mountains: up into the snow & down into the high desert like a rollercoaster. So if you are a fast hiker, you will only be in the heat for one or two days at a time before you get back up to elevation.
So… if you are a fast hiker & have some common sense, then you will probably be OK withe the late start. If its a very dry year, you will have to carry more water & maybe hike some at night. You might get lucky with an unseaonably wet & cool June like Malto did in '11.
Have a great hike!
Happy Trails,
freebird
freebird