Things that are above the earth are also correspondences, things like the sun, the moon, and the stars, and also things that occur in our atmospheres like clouds, mists, rainstorms, lightning bolts, and thunderclaps. The emanations of the sun in its presence and absence like light and shade, warmth and cold, are also correspondences; and so are such corollaries as the times of the year called spring, summer, fall, and winter, and the times of the day—morning, noon, evening, and night.
In a word, absolutely everything in nature, from the smallest to the greatest, is a correspondence. The reason correspondences occur is that the natural world, including everything in it, arises and is sustained from the spiritual world, and both worlds come from the Divine. We say that it also is sustained because everything is sustained from that from which it arose, enduring being in fact a perpetual arising; and since nothing can endure independently, but needs something prior, it therefore needs a First, and if it were separated from that First, it would utterly perish and disappear.
from Heaven and Hell, Sections 105, 106