Richard -
Almost everything is dictated by the weather on the PCT. This year would have been a great year to start early in SoCal & possibly hike straight north to Canada. The last time I thru-hiked the PCT ('05) was a classic flip-flop year, perhaps the best ever. There was heavy snow in the Sierra’s while the Pacific Northwest had one of the lightest snowpacks in 100 years.
If next year shapes up like this one, you could start really early (you’ll still have to deal with reall cold temps even in the desert & the possiblity of a storm) & try to hike NOBO straight thru. If its an avg. year, you could jump around a bit to finish your hike, but be sure to check to be sure that you are not jumping up to another snow-bound area. (In '05, a few hikers skipped up to OR and ran into tons of new snow near Crater Lake)
If you have decent mountaineering skills, you could always just forge ahead into the snow, but as you probably know, snow travel becomes quite tedious after a few weeks!
A great website to check snow depth is postholer.com
happy trails!
freebird