How does the weather contribute to the narrative in Orwell's 1984?

at first
is such a creature of the indoors that sunshine elicits a negative response from him. When he
looks out the window of his apartment early on and sees the sun and blue sky, the world seems to
him "cold" and "harsh," without color. When he meetsin the woods for the
first time, he feels that the sunshine exposes him:

The
sweetness of the air and the greenness of the leaves daunted him. Already on the walk from the
station the May sunshine had made him feel dirty and etiolated, a creature of indoors, with the
sooty dust of London in the pores of his skin.

But as
they relax...