I agree; it is easier to get dehydrated in cooler temps because you're not getting the usual cues.

The powders recommended to my husband were Drip Drop & Liquid IV. I mentioned the unflavored variety to him & said that he could mix it with other things & not necessarily plain water. Getting him to the point of trying something new is difficult though. He views it as an inconvenience vs something that would help him since he has some mental block against hydrating himself [grr].