A-train,
Starting around May 10th - May 17th should be fine. I started April 26th and finished Sept 12th. Or…just under 4 1/2 mos, AND I had to force myself to slow down because I was meeting a friend!
If I had started May 15th, means I would have finished Sept 31st. It is on the cusp of possibly getting a snow storm in the Cascades, but nothing that (generally) sticks around for any length of time. After October you are rolling the dice.
If you do a 4 month pace you will finish in the middle of September when the weather is very nice in Washington.
Just do an honest assement of your abilities and you may want to factor in some time for unexpected delays (i.e the desert heat being harder to deal with than you expected).
As an side, people were a bit skeptical when I said was going to do the Colorado Trail in three weeks. And I did it.
I am just a a “joe average” hiker. Guess what I am trying to say if you are mentally prepared and physically ready to do a 4 month pace it can be done, esp. if you did the AT in 5 mos. A 4 month pace is a a nice middle ground between smelling every flower and rushing by every flower, too.
Best of Luck!
Mags