"It's pretty hot in here, too." It's true - bakeries are never cool, except when they're not being used. Open windows would cool them off, but open windows also mean swarms of insects trying to get into your food, which is something no one wants. Bakers learn how to just deal with the heat. It isn't as hot as it could be, since Peeta's not actively baking right now, but he's also not kidding. There's not much difference between inside and outside except for the lack of direct sunlight.

Still, being rude to Bev isn't something Peeta wants to do, even when he's in a muted temper. Aside from the fact that she's just nice, he's still well aware that the more people he has on his side, the better off he and his allies will be, and he can't afford to break a connection now. "There's a couple of tables and chairs in the front if you want to sit down." Because there's definitely none of that in the actual baking area.