The theme of the poem “Summer Sun” is the power of nature and its ability to bring joy and happiness. The imagery used in the poem paints a vivid picture of the beauty of summer, as well as the warmth that comes with it. Additionally, the poem draws on the idea of how the sun can bring people together, creating a sense of unity and peace. The poem ultimately celebrates the power of summer and the sun to bring happiness and joy to those who appreciate it.