Your best bet is to sail direct to Hawaii as soon as you can't take beating up the coast, anymore. Any time of year is okay though care needs to be taken in the hurricane
season June to November. The Hurricanes that go west hang between 10 and 20 degrees north. You need to stay close to either 10 or 20 degrees and be ready to go left or right and get out of that lane if a storm starts heading your way. The Pacific High is not well formed other than in the summer so winds can be somewhat flukey. Winds are almost always from the E to NE but strength can vary from force 2 to the usual 4-5 of the trade
winds. Summertime, you can almost bet on strong tradewinds.
This is an El Nino year which may make for some unusual weather
. In El Nino years understand the Pacific High may actually turn into a low which would mean strong headwinds. So far, haven't seen indication of it happening and it's not a long term occurence if it does. The El Nino has made for a weak High this year and we have had higher than normal periods of absence of the trades.
The trip north is best made in the summer. I wouldn't want to leave later than the end of September and that could be pushing it. In the winter, Lows march across the North Pacific
averaging one a week and sometimes more often. Summer can have some interesting weather
but usually not more than one per trip, and typically not even that. The summer lows don't have the intensity of the winter lows, either.