Simply, in winter...Get down where the trout are!...otherwise limited success
"...Wintertime angling has been legal since the 2008 season. From mid-November through March, the savvy Truckee angler doesn’t appear on-stream until midday, when the water is warmest. Access in the snow is always an issue. As needed, I strap on snowshoes to reach my preferred water. Their use prevents “postholing” — punching through the snow crust — which can result in ankle sprains and hyperextended knees. In lieu of the snowshoes, rubber or plastic-soled wading shoes are better than felt soles, which collect big clumps of snow.
Winter trout inhabit soft water — mild currents, shoreline edges, and quiet, deep pools. There are only limited times when you can present a dry fly to surface-feeding trout, so the most productive ploy is to probe subsurface, methodically, "low and slow", because the trout will not move much to intercept your offering.
Whichever load-and-lob method you use, be it tight-lining, indicator fishing, or the currently fashionable, “Euro” nymphing, get the fly down. The fish are at the bottom of the stream, and that is where you need to present the fly. I advise fishing searching rigs featuring tandem big/small flies with lead as needed, or chucking streamers.
The aquatic bugs available to trout during the winter are the ever-present midges in all segments of their life cycle, the ubiquitous little black Winter Stonefly adults that pepper the snow banks, and Skwala Stonefly nymphs and adults. Starting in March, the angler will start seeing the first brood of Blue-Winged Olives and March Brown adults, but there will be few trout actively feeding at the surface".