The poem describes a strange, dim day in which everything feels upside down. The title promises "Summer Radiance," but the sky is cold, gray, and autumnal, and people stay indoors to avoid the rain. The day is called a "Lunar Day," as if the moon has taken over the sun's job, and the speaker treats this as a real reversal of roles, a "shock" that has fallen over the whole world.
The speaker sounds quietly unsettled but also a little wistful. The plea to the "little sun" to come out and bring light is gentle, almost like talking to a shy child. The ending adds a twist: a "Solar Night" will follow, so the usual order of things stays flipped. The mood is hushed, gloomy, and oddly curious. Short lines and the repeated phrase "Lunar Day" give it a chant-like rhythm, making the gray weather feel like something strange and a bit dreamlike rather than simply sad.