At first, the speaker seems to be looking back with simple nostalgia. Summer meant running, screaming, ice cream, and a feeling that the world was theirs for three months. The repeated line "I miss the summer" works like a refrain, and each time it opens up a little more: the freedom of childhood, days with no worries about consequences, and even boring afternoons that still felt happy.
Then the poem shifts. The speaker mentions family, closeness, and a time when "no clock existed" that could take them away from the people they loved. That image of endless, unmeasured time makes the ending hit harder. In the last lines we learn that what the speaker misses most is a person ("you"), whose favorite season was summer. The poem suggests this person is gone, though it never says how. The mood is warm and wistful at first, then quietly sad, as the sunny memories turn out to be tied to loss.