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Snow

[In the mountains] there is no substance by which air can be made heavier
or set alight, and thus it is cold.^{*Really not clear about this: what is this "accendere" process that happens to air? >>Ask Winston.}
Because it is hot in low-lying areas,
moist air rises high up,
and it reaches the cold; before it can go any higher
it turns into snow and falls on the plains.
In the mountains, because it is cold, [the snow] lasts,
and in the valleys, it turns into water again.

Hail and Thunder

But when the sun gets warmer in the summer,
the heat brings the moisture higher.
It encounters colder zones, where it solidifies
and turns into ice; then it falls noisily
because it breaks and shatters
into hailstones. But when the air
is dry, it flashes as it strikes
and splits the air in great thunder and lightning.

Wind

The pure air in that [colder] region
resists and rejects change.
And when these exhalations^{*Bad air rising from the valleys} arrive there
it pushes them back down
as if it had been attacked.
The [pure] air gathers great power from this,
so it moves strongly—and that is the wind
that torments the sea and the land.