When icicles hang by the wall, And Dick the shepherd blows his nail, And Tom bears logs into the hall, (1-3)
These first three lines are all about a house, or dwelling, or cabin, or something. We hear of a wall and a hall, right off the bat. Clearly, this poem isn't just about winter, but about living in the winter.
And milk comes frozen home in pail; When blood is nipp'd, and ways be foul (4-5)
Nature tries to destroy the home! Okay, that's an exaggeration, but think about it. Beverages are frozen (milk) and the "ways" home are really "foul." Luckily, there are ways of surmounting these difficulties.
Then nightly sings the staring owl, "Tu-whit, to-who!"— A merry note, While greasy Joan doth keel the pot. (6-9)
The owl preparing to hunt at the same time Joan "doth keel the pot" is a perfect contrast. The death symbolized by the owl is offset by the homely life of Joan's cooking—nice.
When roasted crabs hiss in the bowl, (14)
The image of steaming, "hissing" apples in a "bowl" of ale definitely makes us think of a nice, cozy home, a place of warmth, shelter, and life. We suspect drinking this nice, hot beverage wouldn't be as "homely" if it weren't winter time.