In the first line of the poem the poet uses a

In the first line of the poem the poet uses a metaphor.
A metaphor states that one thing is another thing as in the first line in which the author relates seasons to celebrations.
A metaphor is a divice of speech that depicts an object or action in a way that isn’t literally true, but helps explain an idea or make a comparison.
It is not a simile because similes require the words like or as in order to create the comparison.