Most poems about winter ending are poems of relief. "calendar" starts from the opposite place: "it pains me to know / that there was more that melted away / than just the snow." The thaw should be good news, but the speaker has lost something that was part of winter and went with it. The poem never says what. That silence is deliberate, because the loss belongs to the speaker alone and the seasons are only the language available to describe it. The central idea is a paradox. The speaker hated winter and wished it over, yet its leaving is a wound, and that wound turns out to be a kind of training for a bigger one.
The poem's structure follows the calendar of its title, though not in a calm way. We begin at the end of winter, jump ahead to the flowers and birds of "next spring," and finish with spring already "leaving abruptly." The speaker is grieving a season that has not arrived and then grieving its departure before it begins. This is anticipatory grief, the dread of a loss that hasn't happened. The comic-sounding "i nearly have a heart attack" is hyperbole, but it shows how physical that dread is. The speaker also "carries the guilt of winter on my back," an image that turns a season into a load to be hauled around. Nature's cycle keeps turning, while the speaker's emotions stay stuck at the point of loss.
The language is plain and often blunt. Calling winter "the most stupid season" sounds like something said aloud, and the lack of capitals and punctuation, with the lowercase "i" repeated throughout, strengthens the feeling of a voice thinking in real time. The rhythm is loose and conversational. The long line "and every-time i stop to think of the season to come" stretches out like a spiral of worry, and the next line cuts it short with "i nearly have a heart attack." That abrupt drop in length mimics the lurch of panic.
Rhyme is used here in an unpolished but effective way. "Know" and "snow" frame the opening. "Spring" and "sing" give a sweet, bird-song couplet that the speaker immediately undercuts by turning to guilt. "Back" and "attack" bring the poem down hard, and "season" and "reason" pair up neatly before the poem starts to turn on the word "reason." At first the speaker wanted spring "without a reason," meaning without justification, as though winter were pointless suffering. Then comes the realization that "there is a reason." The line break after "reason i" leaves the "i" hanging at the end of a line before the next line says "had to be saddened by winter." The speaker is briefly stranded between realizations, which suits the moment of understanding.
The final lines carry the poem's real argument. Winter is "drifting away," a soft, slow verb, while spring is "leaving abruptly." The speaker is "broken" by one and would be "shattered" by the other. Both words suggest damage, but "shattered" is more final, and the poem implies that winter's sadness has cushioned the speaker for what comes later. The last sentence is grammatically tangled. "If i hadn't been broken... than i will be shattered" shifts tense and uses "than" where "then" seems intended. Whether or not that is a slip, the comparison the word suggests, broken versus shattered, is exactly what the poem is weighing. The messiness fits a speaker who is working out a thought as they say it.
As for significance, "calendar" is a modest, unpolished poem, and it doesn't pretend otherwise. What makes it worth reading is its honesty about a feeling many people recognize but rarely say aloud: that pain can arrive in advance, that we can mourn things we once wished away, and that one loss can teach us how to bear the next. For students, it is also a useful example of how simple words, a few well-placed rhymes and a familiar image like melting snow can carry real emotional weight without any elaborate technique.