I learned something last week while on vacation in Mexico: Spray-on sunscreen doesn’t work that close to the Equator — not even the 45 SPF kind.
After getting fried the first day, I took a break from the sun until three days later when we went snorkeling. I had brought along a sample size of something called Aloe Gator with a 40 SPF that claimed to be waterproof, sweat-proof, and last 4-8 hours. My husband and I squeezed out every last drop of that and lathered as much as we could on our sun-ravaged skin. When we ran out, we sprayed more 45 SPF and hoped for the best.
Turned out the stuff worked. Well. There was a clear dividing line between the Aloe Gator and the spray-on sunscreen (hint: we were red, or even redder than we had been, anywhere only the spray-on stuff had gone).