Is it safe to take my 15 year old out in the 98 degree heat? (no car A/C)?

I have no A/C in my black car. Its 98 degrees outside. Im going to my father in laws house for him to add fluid to my air conditioner. It is safe to take my 15 month old out?I can't find a baby sitter. The drive is 30 minutes. I gave him some pedialyte