Essentially, this famous ode is an extended apostrophe to the powerful west wind, that Shelley refers to as "thou breath of Autumn's being." After addressing the wind and describing its effects, the speaker of the poem declares that the wind is both "Destroyer and preserver," and finally ends by imploring the wind to share its power with him so that his words may be spread throughout mankind and might spark new life in the world.
It is important to note that at the end of the very first stanza, the speaker makes the wind seem like a life force or divinity:
Wild Spirit, which art moving everywhere;
Destroyer and preserver; hear, O, hear!
Consider to the way that the wind is presented in the first stanza and how the poem equally focuses on the wind's act of "destruction" and the role it plays in creating new life. This reinforces the personification of the wind as a kind of god that brings resurrection and annihilation in its wake.
It is these dual aspects of the West Wind that the speaker of the poem seizes upon as he closes his verse by asking to be the instrument of this powerful entity when he says "Make me thy lure, even as the forest is." His attempt to powerfully identify himself with the West Wind and to share these same characteristics are so that his verse can be used to impel a rebirth amongst humanity:
Drive my dead thoughts over the universe
Like withered leaves to quicken a new birth!
And, by the incantation of this verse,
Scatter, as from an unextinguished hearth
Ashes and sparks, my words among mankind!
Be through my lips to unawakened earth
The trumpet of prophecy!
Note the paradox implicit when the speaker describes words as "ashes and sparks." Yet a smouldering hearth contains both dead ashes, the inert words of a poet, as well as the fiery sparks that represent the life in the poet's words and their ability to inspire and "ignite" others.
Thus the poem, whilst it is clearly a pageant to the power of nature as represented in the West Wind, can also be said to be about the nature of being a poet and also the desire to communicate Shelley's own experience of being a poet through his verse being read through generations, "blown" metaphorically by the West Wind.