Changing conditions

One of the most significant changes in fishing conditions - known by every fisher in the world - is the changing light - most clearly demonstrated by the importance of sunups and sundowns.

Water moving

Water conditions change from day to day and one location varies from clear, calm water to muddy water with high waves. The fish are there almost no matter what, and often rough weather offer better fishing than a calm surface.

Knowing is the key

Knowing the significance of the changes is very important, and knowing the way wind, current, clouds, rain etc. influence local waters can be a key to successfull fishing.

Better fishing

Any water movement (tide, current, waves) will give you better fishing, but falling water is normally best in these parts of the world.
Also we have a lot better fishing when currents go north (often in southern winds), but you probably won't have the same problem. If you fish bays, fjords, estuaries etc. my guess would be that water moving outwards would be best. That's true here at least.

'High' season

Also as a whole, fishing can be very good all year round, but is probably best just before the fish enter the streams to spawn (autumn here). Other factors seem to have less effect at that time, but... the fish can be quite picky with what they eat. Ideal for an FF'er.