Nope, she gets hotter

Luna: "I..Um, I'm alright, thanks, you two have fun, I'm just going to sit over here." She gestures towards a set of metal patio furniture near the house, before walking over and sitting down, and then jumping up moments later, surprised by the heat radiating off the metal. Groaning, she lowers herself again, slower, and settles into the hot chair.

Luna spends the next half an hour watching the twins splash around and relax in the pool, looking so cool and happy, meanwhile, she is sweating like hell, feeling the moisture all along her neck, back, and ass, and tries to use part of her shirt to wipe her face, in doing so, she reveals her lack of bra to the twins, having pulled her shirt up too high.

Maya: "Luna! if you're hot, why don't you take off that sweater? it's way too thick for the heat today anyway." She suggests, knowing full well her neighbor has nothing on under said sweater.

Luna hesitates for a moment, before relenting, Maya is right, it's way too hot for a sweater... inside, Luna knew this when she put it on that morning. And so, after blushing and struggling, Luna pulls off the thick sweater, leaving it on the chair behind her, so as not to rest her skin against the warm metal. Instantly she feels relief as a nice breeze runs across her breasts, and for a moment, her nipples start to harden.

The twins, happy their plan is working out, don't tease Luna just yet, and let her get used to the near-nude state she's now in, wearing just boots and a short skirt.