Originally Posted by
Grumbleguts
The three stanzas each show an aspect of autumn.
The first links it closely to summer, implying that autumn is the fulfilment of summer, its coming to fruition.
The second shows the traditional jobs of summer through the poetic trick of personification, representing the people undertaking the tasks as if they were Autumn himself.
The third is a counter to the first and links autumn with the approach of winter.
Reread the poem with this in mind and I am sure that you will see many more of the references in it.
As Bandini says, Keats died young. Although he was in the springtime of his life in respect of his years he was also in the autumn in respect of his early death from TB.
However he did not have TB at the time that this poem was written in 1817. He contracted the condition while attending his dying brother the following year, so any allegory that exists is probably imposed upon the poem by the reader's hindsight. (Sorry Bandini.)