Gear

Sunscreen

A tube of sunscreen in a rucksack.

Factor 30 or 50, physical or chemical filter, and why sunscreen matters even more on snow than at sea.

UV radiation is not weakened by altitude or reflection — for every 1,000 m you climb, UV rises by about 10 %, and snow reflects 80–90 % of the radiation back at your face. That means a sunny day at 1,500 m above sea level in April can deliver more UV exposure than a summer day on the beach. Sunscreen is not a summer-only thing.

Factor — what does it mean?

SPF (Sun Protection Factor) measures how much longer you can stay in the sun before skin damage occurs, compared with unprotected skin.

  • SPF 15 — blocks about 93 % of UVB
  • SPF 30 — blocks about 97 % of UVB
  • SPF 50 — blocks about 98 % of UVB

For trip use, SPF 30 is the minimum, and SPF 50 is recommended for snow, high mountains and longer exposure. The difference in percentage is small, but the difference in tolerance time is large — SPF 50 lasts twice as long as SPF 30 before you have to reapply.

UVA and UVB — broad-spectrum protection

UVB is what burns the skin quickly. UVA is what causes long-term skin damage and an increased risk of melanoma. Broad-spectrum sunscreen protects against both — check that it says “UVA” or “broad spectrum” on the packaging.

In Norway, the UVA symbol (a circle with “UVA” inside it) is standard on good sunscreen.

Physical vs chemical filter

Physical filters (zinc oxide, titanium dioxide) sit on the skin and reflect UV. They start working immediately, are less allergenic and look more “white” on the skin. Good for the face, especially the nose and ears.

Chemical filters (octinoxate, avobenzone and others) are absorbed into the skin and convert UV into heat. They are easier to apply, less visible and start working after 15–20 minutes. Standard on most trip creams.

For trip use, a combined chemical sunscreen SPF 30–50 is standard. Many people also choose a physical SPF 50 stick for the nose and ears.

Amount — use enough

The common mistake is using too little. Recommended amount:

  • Face and neck: a teaspoon
  • Each arm: half a teaspoon
  • Each lower leg: a teaspoon
  • Whole body (in shorts and a T-shirt): about 30 ml (a child’s handful)

Reapply every 2–3 hours, and after heavy sweating or a wet face.

Particular challenges

Snow blindness affects the eyes in the same way sunburn affects the skin — the eyes “burn” from UV reflected off snow. Symptoms appear 6–12 hours after exposure: painful, red, gritty-feeling eyes. Prevention: good sunglasses with UV400 or better, ideally with side coverage.

Facial areas you tend to forget: nose, ears (especially the tips), the back of the neck, the forehead beneath a hat, lips (use an SPF lip balm).

Packing

Tube in the top of the rucksack. In the cold — keep it in an inner pocket in winter, because sunscreen stiffens at low temperatures.

Maintenance

Check the use-by date. Sunscreen loses effectiveness after 1–2 years, especially if it has been in sun or heat.

Sunglasses → (external — its own PDP is on the way)

Text: Snuitide (2026), based on recommendations from Helsedirektoratet and Kreftforeningen.