I'm pretty sure there is a set of rules for all this, but I haven't found it yet. I firmly believe that resident trout turn way down during the day on a full moon (and in the couple of days before). I started a thread about that a while back, and I seem to recall most who responded saying that they had similar opinions, but as is usually the case, there were exceptions who said they had experienced the best trout days of their lives on a full moon. I haven't been able to identify any reliable guidelines for fishing salmon and steelhead as regards the phase of the moon. I almost had myself convinced that the full moon was bad for them too, but this last December, I had what I suspect will go down as my best ever numbers day on steelhead on the day after the peak of the full moon. It's probably worth noting that the conditions, moon aside, were similar to what Sky-Guy says he likes. In this case, the fish weren't concentrated so much as plentiful, holiding in every sneaky lie, and ridiculously willing to bite.

As for the barometer, my research turned up the same results as steeliedrew's but my experiences haven't always followed those rules. I will say that I tend to feel more confident on days when the moon is something other than full, the barometer is slowly dropping or steady, and the wind is coming from somewhere between south and west, but like most are saying, the time to go is when you can go. Bring a positive attitude (not usually too hard when going fishing), fish with confidence, and take comfort in the fact that you will do as well as conditions and the fish gods allow.

The one thing I think we can be sure of is that having more fish around makes for better fishing in all weather conditions. For that reason, I think that the overall weather pattern (El Nino, La Nina, etc.) may have more to say about how much success we have in a given season than specific weather conditions. La Nina seems to bring the best possible conditions to our rivers and the ocean, if the numbers of fish I have seen in the past couple years, relative to the few years prior, is any indication.