In our part of Idaho Silver Ck downstream from Hwy 93 between Richfield and Carey is open all year. Catch and release and some nice fish this time of year. Twice within the past two weeks Rooney (our German wirehair pointer) and I have taken partridge in the a.m. and then released a few trout in the p.m.
The Little Wood is open year round and just below the confluence with Silver Ck holds good fish.
Then, too, parts of the Big Wood are open. Even the desert is a good place for trout in the winter.
Of course, if you like big fish tugging on your line, there's steelhead fishing throughout the winter north of us a couple of hours on the Salmon River.
Allen R