A recent article at Time.com extols perhaps the single best virtue of PM showering, noting that if you want to improve your sleep, showering at night is the way to go.
“Experts say there's evidence that a night shower can help you drift off,” Abigail Abrams writes, “if you time it just right.” But there’s more good than just good sleep that can come from a moonlight shower.
Check out the full list of reasons you should trade the morning shower for one before bed, at TreeHugger.com