Apparently there's a lot of pseudo-scientific quackery and misinformation about whether or not cold or body temp or warm water or whatever is "better" for you, "absorbed faster", "emptied by the stomach faster into the small intestines where it is absorbed" and so on, depending on what is being measured and what is subjectively "better". I even saw a reference to the "energy" used by the body to warm the water to body temperature can hurt performance!
Unfortunately my quick Google search didn't result in anything definitive (or from an obviously reputable source). This would be a great research topic for an "ig nobel prize".