Mal both was and wasn't used to hot. You didn't get hot in space - there was something about cold being the absence of heat or something that he didn't understand, but at any rate any heat they had in space came from the ship itself, and it wasn't like they had the resources to keep it balmy. But at the same time, most of the border moons were edging on pretty close to their suns for a lot of the time, and he usually didn't dress for it.
Course, he was usually better prepared than this. It wasn't every day that he woke up to discover he'd been kidnapped.
...
It was at least every other week.
He had run into Kaylee in the hallway, looking entirely too not-clothed for his liking, really, and she had giggled and assured him that it was the latest style in swimwear. Whatever... that meant. She'd then invited him to the pool, and he really thought this whole thing was a little bit too bizarre for him to really grasp, but it was Kaylee and she was familiar so he'd followed along obediently as she led him up to the roof. Where he'd met with the aforementioned heat problem.
"Where... d'you say this was again?" he asked, holding a hand to his head and looking up at the sun as though that would clue him in to where he was.
"We dunno Cap'n," Kaylee said, gazing around the pool cheerfully. She spotted Jaime tanning, and offered her a wave whether or not she was looking over. "Hullo! Hope you don't mind if we..." she waved her hand in the direction of the pool indicating her intentions to go swimming.
"You seem well adjusted to that fact," Mal said through gritted teeth. He wasn't too sure he was adjusted to the fact that he'd been kidnapped to be studied by some scientists. His eyes moved in the direction Kaylee waved, and he frowned slightly, feeling vaguely uncomfortable about just how casual the females around here seemed to be about showing skin. But he supposed that was just him being old.