During the summer I tend to grab for a tinted moisturizer more than a foundation. It's a lot lighter and has more SPF than foundation. The tinted moisturizer I use is e.l.f's tinted moisturizer in nude. Right now I'm still to pale for it since I haven't tanned much.
I also have to have a waterproof mascara and eyeliner. For eyeliner, I use Maybelline Unstoppable in onyx. It's waterproof and smudge proof which makes it last all day. For mascara, I like to use Maybelline Mega Plush Waterproof formula. It's really light and doesn't flake on me. It doesn't make lashes brittle or crunchy.
My last summer must have is Maybelline baby lips or EOS. Both are super moisturizing and perfect for summer time. Comment your summer must haves! :)