Don't go outside? But tanning is good though why wouldn't you want to?
Use sunblock everytime you go outside. And I know it can be really uncomfortable in a hot weather, but I suggest you to wear a long sleeve and long pants everytime you go out. And do not swin in the middle of the day or in the morning, afternoon is a much better time if you don't want to get tanned.
I'm not an expert, but maybe if you don't stay outside too long? I live in south Alabama and it's one of the hottest and most humid places in the United States.
If you don't want to be tan, bring an appropriate sunscreen with you. Also, use google to see the weather at where you are going.
You mean by doing something completely outrageous and unexpected like put on some sun screen? What do you think Einstien? Think you could manage that? Or no?