It's Nacho Funeral (Mexican Mystery 3)

“If my calculations are correct, and they haven’t been wrong since 1987 and even then that didn’t really count because nobody predicted that typhoon, we’re going to be in the direct sun for the absolute maximum amount of time. Ha! We’re in for a treat today!”

I blinked at him, unsure what exactly he’d just said, then began to lower myself down onto one of the loungers. I’d grown up watching my share of sun lounger mishaps on You’ve Been Framed, and had a sensible distrust for the plastic contraptions.

“Stop, lassie! Not so fast!” Uncle C commanded.

I froze, my body in a squat for the first time in my life, unsure whether to stand or sit or remain as I was.

Uncle C opened the huge beach bag’s zipper and pulled out a towel, which he presented to me with a flourish.