The single most important factor that determines a fly angler's approach to a stretch of water isn't the time of day, nor is it a hatch of insects or even the character of the water itself. It's the season. From spring and summer through fall and winter, changes in weather dictate changes in strategy. This can be intimidating. If fish were biting here a month ago, why are things so different now? Where to go where they might be better? The seasonal...