Dickinson begins by praising winter, and by the last line she has taken most of it back. The poem's joke is that winter's goodness is real but hard to enjoy while he is in the house. The "Hoar Delights" of the season, its frosty, whitened pleasures, are a taste for people who have overindulged. They are offered to "Intellects inebriate / With Summer, or the World," minds so drunk on warmth, color and busyness that they need sobering up. Winter is a cure, and cures are rarely welcome.
The first stanza turns on odd, precise word choices. "Hoar" means frost-white, and it also carries a hint of "hoary," or old, so winter arrives looking like an elderly man. "Italic flavor" is the stranger phrase. Italic type is slanted, lean and fine-lined, so the flavor of winter seems to be thin, angled and understated, a contrast to the rich, rounded taste of summer. That reading is an interpretation, but the printing metaphor fits the way the poem treats pleasure as something to be read and judged, not gulped. The word "inebriate" belongs to the same game. A Latinate, almost scholarly word for drunkenness, it makes the "Intellects" sound faintly ridiculous, as though thinking itself had been on a spree.
The second stanza turns to similes, and none of them is quite comfortable. "Generic as a Quarry" suggests something plain and elemental, a place where raw stone is cut out, belonging to no one in particular and lacking decoration. Then comes "hearty -- as a Rose," which pairs winter with the most pampered of flowers. The comparison is a puzzle. A rose is usually fragile, yet "hearty" suggests robust, wholesome and nourishing, and perhaps also something of the heart. Winter ends up as both stone and flower, bare and warm at once. Dickinson doesn't resolve the contradiction, and that is part of her point: the season is difficult to sum up.
Then comes the sting. "Invited with Asperity" is a perfectly chosen phrase, since "asperity" means harshness or roughness of manner, and it was also used of severe weather. We invite winter in a curt, grudging tone, the way one invites a relative one cannot avoid. The final line, "But welcome when he goes," lands the joke. Winter earns real appreciation only at his departure. Personification has been at work all along, with "his" in the first line and "he" in the last, and it quietly turns the season into a guest who is respected, put up with and then happily waved off.
The sound of the poem helps the effect. The lines alternate between longer and shorter, roughly eight syllables then six, a pattern close to the hymn measures that Dickinson often borrowed. The first stanza avoids tidy rhyme. "Delights" and "inebriate" barely connect, and "yield" and "World" share only a faint echo of consonants. The second stanza tightens up: "Quarry" and "Asperity" chime on their endings, and "Rose" and "goes" make a full rhyme. The poem is most orderly at the moment it says goodbye, so the neat click of "goes" sounds like a door closing behind the guest. The dashes, one after "good" and one at the very end, are typical of Dickinson's style, and they leave small pauses where the reader must decide how much irony to hear.
The poem is significant for how much it does in eight lines. Its vocabulary swings between the long, learned words (inebriate, Asperity, Generic) and short, homely ones (good, Rose, goes), and the friction between them is where the humor and the thought come from. It also gives a more honest account of seasons than the usual cheerful praise. Winter is good for us, and we are not obliged to love it. The poem lets two feelings stand side by side, respect and relief, and it makes the reader smile at recognizing both.