In the interest of good literature, not necessarily crime, What kind of weather, or setting do you find to be particularly creepy or more to the point, uncomfortable for your imagination and therefore, adding tension to whatever is going on in the story?
With hurricane Ike coming through (we have his tail end), When I got up this morning there was this weird light shining up the road, only on the road, like a car was stopped and just had its headlights focused on that side.
There was no car, it was dark on the side of my house and in the woods just beyond the light. It was the weirdest thing I think I've ever seen.
I did go check to see if a car wrecked at the corner. Imagination is a powerful thing! Thats how I know there wasn't one.