Winter Conditions Fishing for smallmouth bass during the winter is all about focusing time and energy on the right habitat. If you float the river, hitting all the water that holds fish in the summer months, you will likely turn up empty-handed. As water temperatures plummet through the month of December and into early January, smallmouth bass retreat to their winter holes. The size of their winter holes can vary depending on the size of the river. On larger rivers like the New or the James, winter holes can be significantly larger when compared to smaller tributaries. On bigger rivers, prime winter holes may have depths of up to 15 feet or more and might be 30 to 50 yards or more long. On smaller rivers, winter holes might only be five to six feet deep.