I spend a lot of time replacing white skies in my pictures because they are usually distracting. I mentioned this is in a blog just two days ago regardin the shot from Indonesia. However, in art there are always exceptions, and this picture of two stallions battling for dominance is an example of where a white sky works. One of my favorite color themes in nature photography is white on white, and that's exactly what I captured here. In fact, had the sky been blue, I wouldn't like the picture as much.
Even though there was enough light to use a low ISO, I selected 640 ISO because I wanted a shutter speed fast enough to freeze every water drop. My settings for this picture were 1/5000th of a second, f/4, and I used a 70-200mm lens set to 90mm for this shot.