Why does Bradbury compare the Hound to autumn? What other mention of autumn have we seen in the book?

I think that Ray Bradbury compared the Hound to Autumn because the season is known for creeping up on people. The summer wanes and Autumn begins to show quickly,

 "He could feel the Hound, like autumn, come cold and dry and swift, like a wind that didn't stir grass, that didn't jar windows or disturb leaf-shadows on the white sidewalks as it passed. The Hound did not touch the world." 

Here is another quote about autumn:

"The autumn leaves blew over the moonlit pavement in such a way as to make the girl who was moving there seem fixed to a sliding walk, letting the motion of the wind and the leaves carry her forward."