There's really no sure bet, but I have also noticed good fares about 5 months out, and they seem to edge up at the 4 month mark. They can then go down for seat sales at the 3-2 month mark. Crazyh.
Someone here said don't think you have to buy return fares, and that is good advice. Alaska Airlines now will credit you back the difference if your flight goes down, so you could book your outgoing leg and if the prices go down you can apply the credits to the purchase of your return leg. (Hope that makes sense

) I am really glad they do this now as it takes some of the stress out of getting the best fare.
Good Luck!