Throughout most of the poem, the natural world is transforming to winter. The most obvious transformation that the speaker notes is the west wind becoming powerful and blowing the leaves off the trees, moving the clouds across the sky at high speeds, and churning up the waves of the sea.
As the speaker witnesses the powerful west wind blowing the leaves—and the waves and the clouds—everywhere, he wishes with all his heart that the wind, or some spirit like it, could blow the leaves (pages) of his writing to the far ends of the earth. He wishes for his message, too, to travel everywhere. He cries out:
Oh, lift me as a wave, a leaf, a cloud!
The speaker's transformation across the course of the poem is from despair to hope. At first, the speaker feels anguished at how difficult it is to spread his words, saying:
A heavy weight of hours has chain'd and bow'd
One too like thee: tameless, and swift, and proud.
In other words, he is explaining that even though he has a proud and wild spirit like the west wind, he is chained and bowed down like a prisoner because of his bodily limitations. He suffers, stating:
I fall upon the thorns of life! I bleed!
By the end of the poem, however, he finds new hope. He calls out to the west wind to scatter his words across the earth. He perceives the hope of a new beginning in which his ideas will grow and flourish, which he compares to spring:
If Winter comes, can Spring be far behind?