If you don't wear sunscreen on your face every day (even when its cloudy out) today is the day you should start!
My tried and true favorite is Neutrogena's Ultra Sheer Face Sunscreen with Helioplex. It comes in different SPF's I happen to use SPF 60 at the moment. This sunscreen will protect you from harmful UVA and UVB rays which is ultra important.
What I love about this products is that its light weight, fragrance-free, oil-free, non-greasy, non-comedogenic and waterproof! Its even gentle enough for those with sensitive skin and is dermatologist approved.
What I like to do is put a tiny bit in the palm of my hand, followed by a bit of my regular moisturizer and mix it together in my hands before applying it all over my face and the front and back of my neck. I find that for me its easier then waiting for one to dry before applying the next.
Tip: Make sure to apply sunscreen to the back of your neck especially when wearing your hair up. Its often forgotten but can just as easily be damaged by the suns harmful rays!