In this apocalyptic poem Shelley characterises it as a destructive and fearsome force, yet it is also a harbinger of the inevitable coming of Spring. It is, therefore, both Destroyer and Creator, and Shelley sees the West Wind as a symbol of the regeneration which will follow the destruction and Death of Winter.
In a personal sense Shelley addresses the Wind as a force which will reinvigorate him, the Wind of Spirit and Inspiration, at a time (aged 27) when he feels his own powers as a poet are on the decline.
Socially and politically, the Wind represents the destructive and revolutionary energies which had been seen in Europe over the previous thirty years, overthrowing long-established and corrupt social orders in France and Italy.
Would there be a "Spring" to follow the destructiveness of this European Autumn and Winter, leading to a new renaissance in political and social affairs? This symbolism is most clearly evident in Section III of the poem. In spiritual terms the West Wind, invoked here as either god, or manifestation of the divine Spirit, is both celebrated as a harbinger of new creation, manifested in Spring, and also feared for its destructiveness and great power.
The "West Wind", in a spiritual sense, becomes an abstract expression or manifestation of the spirit - the anima, the "divine wind" - within Nature, a driving force behind the turning wheel of the seasons and the cycles of Life-and-Death.
The final effect of the poem is ambivalent, a mixture of depression and hope, signalled by the question-mark which ends the poem. Is Shelley here affirming that Spring (in a personal, social and spiritual sense) will inevitably follow this Winter, or is that simply imposing a human construction on Nature, with no guarantee that new life...