Heavy - duty all - day sun protection calls for the big guns. (mindbodygreen.com)
It isn't strong enough to use alone for all - day sun exposure but is a great every day option for mild sun protection and skin health. (wellnessmama.com)
For example: you write For a cool autumn day the sun is likely providing 100 W / m2 of energy. (theinconvenientskeptic.com)