Williwaw [wil-ee-waw] If you're out adventuring and you see a williwaw headed your way, take cover. Dictionary.com cites this as "a violent squall that blows in near-polar latitudes, as in the Strait of Magellan, Alaska, and the Aleutian Islands." This may very well lead to what's known as a three-dog night.
Crepuscular-ray - When you sit on the porch admiring the sunset, you might be looking at one of these. We define it as "a twilight ray of sunlight shining through breaks in high clouds and illuminating dust particles in the air."