The Costa Rica sunburn nobody warns you about

It happens all the time. Somebody arrives, spends a happy first morning on the beach and spends the next two days indoors. Uvita sits about nine degrees north of the equator, and the sun here is not the sun you know from home.

How strong it is

The World Health Organization's UV index starts at 1, and anything from 11 upward is classed as extreme. Costa Rica's national weather institute regularly reports readings between 10 and 13. At those levels unprotected skin can burn in minutes.

Cloud does not save you. Up to 90 percent of UV passes through thin cloud, which is why overcast afternoons in the green season burn people who thought they were safe. Sand reflects UV back up at you and so does water, so shade on a beach is only partial protection.

The routine that works

The United States Centers for Disease Control and Prevention recommends a broad-spectrum sunscreen of at least SPF 15, reapplied every two hours and after swimming, sweating or towelling off. Most people put on too little and reapply too late. On this coast we would go higher than the minimum and treat the two hours as a rule.

Sunscreen is the last line of defence, not the first. A long-sleeved swim shirt never washes off. Add a hat with a brim and sunglasses, and plan the day around the sun: beach early and late, with lunch and a rest in the shade through the middle of the day.

The places people forget

The tops of the feet, the ears, the back of the neck, the parting in your hair and the backs of the knees. On a boat or a surfboard there is reflection from every side, so cover up more than you think you need to.

If you do burn

Get out of the sun, cool the skin, drink plenty of water and stay covered until it heals. Blistering over a large area, fever or chills are reasons to see a doctor. Tell us and we will point you to the nearest clinic.