It seems like each February there is always a week that we get sunshine. It can be spectacular. Maybe you'll get lucky and it will come when you are here. Outside of that, count on typical wet-side conditions . . . overcast and periodic showers. Not great but not bad enough to keep me from fishing.
I haven't fished San Juan Island much but I've fished Orcas Island quite a bit. PM me if you want more details. There are definitely options worth pursuing IMO.