Jason Reif, a client of Rob Snowhite’s, with striped bass, left, and hickory shad. (Rob Snowhite/Rob Snowhite)

Rob Snowhite spends much of his winters waist-deep in the Potomac, and some people pay him to tag along. For about the past eight years, the former Fairfax County Public Schools biology teacher has been coaching people on the fine art of urban fly-fishing. He’s managed to carve out a niche market among the area’s overworked and overscheduled residents who for whatever reason don’t make it to quintessential fly-fishing regions such as Western Maryland, Pennsylvania and the Chesapeake.

“A lot of people fly-fish for the escape or distraction from everyday routines,” Snowhite explains, adding that he often has clients squeeze in a weekday morning or lunchtime lesson.

It’s unpredictable what they’ll find. Washington is located along the migratory path for many fish species, and “what’s here one month might not be here the next,” Snowhite says.

Alex Beschloss, a Washington native studying medicine in Philadelphia, has been fly-fishing with Snowhite since 2014. “It is a fun challenge to navigate waters that are interwoven with urban structures,” notes Beschloss, adding that he loves finding fish where no one would expect them to be — like the Tidal Basin. Even when the temperature drops below freezing, there are still plenty of fish for the catching.

Here are some of Washington’s most bountiful locales this winter:

Four Mile Run, Arlington: A literal hot spot for fly-fishing, the water treatment plant here churns out warm water, where largemouth bass, carp, bluegill and redbreast sunfish will congregate.

Burke Lake, Fairfax Station: Walleye and muskie are cool-water fish, and Burke is a warm-water lake, says John Odenkirk, a Northern Virginia district fisheries biologist. Nevertheless, the lake is annually stocked with these fish, which do well in winter and spring.

Holmes Run, Falls Church: Snowhite says water coming over the Lake Barcroft Dam “keeps the stream flowing and aquatic life abundant,” with ample trout for most of the winter.

Beginner and experienced fly fishermen alike can join Snowhite and the Tidal Potomac Fly Rodders fishing club at 7 p.m. Feb. 12 for its free monthly event to tie flies and talk fly-fishing at Whitlow’s on Wilson (2854 Wilson Blvd., Arlington).