Shelley imagines April and May as a pair of artistic sisters, each with her own role in creating the landscape we see. April comes first, lightly drafting the scene: the bare outlines of trees, the first soft shapes of green. Then May steps in as the painter, the “limner” whose job is to fill that sketch with brilliant, joyful color. The word “gay” here carries its older sense of bright, lively, and full of cheer.
There’s a real tenderness in calling April May’s “sweet twin.” The speaker isn’t just ticking off the calendar; he feels a quiet wonder at how the seasons hand things off without a break, each one building on the other’s work. The mood is delicate and hopeful, caught in that fleeting moment when spring stops hinting and fully arrives. Only two lines survive, but they feel complete — a small, bright window into a world being gently brought to life.