Oily scalp in summer

I tried dry shampoo for the first time last week. I washed my hair the evening before, but oil started slowly building up in the afternoon. It was work, and I had plans for the evening—what should I do? Suddenly, I remembered I had put the dry shampoo sample in my bag, so I decided to use it. It came in a spray bottle, so it was easy to use. You just spray the white powder onto your hair, wait two minutes, and brush it off—that's it. The description said it lasts for 48 hours, and I thought, "No way," but my hair really didn't get oily for 48 hours. I think I'll be using this often during the summer. It seems like a good product.