An idea for the background of my animation

I have shown my animation to friends and family, and an opinion which keeps coming up is that, while the attention should be on the dancers, there needs to be a background for my video, as it looks very basic and unfinished with a plain white background.

Some suggestions were very unrealistic, such as hand-drawing a background for each frame. This would double the workload, and, even though it would look great, I won't have enough time to create something worth watching.

However, a suggestion which I really liked was making a static film of the sky, over a couple of hours, and fast-forward it so the clouds move faster.

This background would look good, and at the same time be subtle enough to work with the animation.

I could also change the light, saturation, or add a filter for a greater effect!

I found a clip on YouTube which shows more or less what I am aiming to achieve (but mine will be better):