A wide brim sun hat which is certified UPF 50+ will make sure that at least 98% of UV direct from the sun is blocked by the fabric itself. Even if a sun hat shades your face completely it may only reduce your sun exposure by around 50% as indirect UV can reach your skin depending on where you are by bouncing off the surfaces around you.
The wider the brim of your sun hat the better for maximising coverage for the face and reducing indirect UV. A sun hat is considered by the Cancer Council Australia to have a wide brim when the brim length is more than 6cm for adults, 5cm for children. A sun hat with a neck flap which is also known as a legionnaire provides additional protection for your neck.
Sun protective clothing which includes sun hats are the front line of sun protection. Dermatologists recommend UPF 50+ sun protective clothing as the most effective way to protect yourself from the sun.
SPF 50+ sunscreen is also an effective way to protect your skin from the sun. Sunscreen should be part of your daily skincare routine. The challenge is that you have to apply enough and reapply. If you are applying to your face only, it is recommended to apply half a teaspoon at a time. If you are applying to your whole body, it is recommended that you apply seven teaspoons of sunscreen which is equivalent to 35ml.
You should apply sunscreen around 20 minutes before sun exposure and then every couple of hours. Reapplication should be even more regularly after being in the water, if you have rubbed off the sunscreen or if you have perspired heavily.
The bottom line is that having protection from an SPF50+ sunscreen and a broad brim sun hat with a sun protection rating of UPF50+ would be the best way to protect yourself from the sun. That way, you are giving yourself the best possible chance of avoiding a sunburn, premature skin ageing and being diagnosed with skin cancer.