The only thing I can think of is that the heat makes the orange odors more volatile and this, merged with the increase in mucosa humidity, makes the orange odor smell more in the mouth," Lundström said in an email.
— NPR investigates the claim made at the subreddit /r/ShowerOrange that oranges taste better if you eat them while you're showering, then they talk to Johan Lundström of the Monell Chemical Senses Center for an expert opinion. (Any perfumista who has tested a light citrus cologne outside on a hot humid day, and then tested it again in air conditioning, can relate.) Read more at Do Showers Make Oranges Taste Better? NPR Investigates, and note that @nickrgilbert (and quite a few others) on Twitter gave it a try too.