A child's skin is not a smaller version of an adult's. The stratum corneum is thinner, melanin production is immature, and the immune response to UV damage is slower. 80 % of lifetime sun exposure happens before age 18, and a single blistering childhood sunburn doubles the risk of melanoma later in life. Protection is not about being paranoid — it's about getting the basics right at the right age.
By age, what to actually do
0–6 months — keep them out of direct sun
No sunscreen on bare skin at this age (the AAP exception: small amounts on hands and face if shade is impossible). Babies' skin absorbs chemical filters more easily and the kidneys clear them slowly. Use shade, a wide-brim hat, long-sleeved cotton in light colors, and a stroller canopy with UPF 50 fabric. Avoid window-side car seats during peak hours.
6–24 months — minerals only, lots of fabric
Use mineral (zinc oxide / titanium dioxide) SPF 30+ on every exposed area, 15 minutes before going out, reapplied every 2 hours and after every dip. Avoid sunscreens with oxybenzone, octinoxate or fragrance. A long-sleeve UPF rash guard at the beach removes 90 % of the application area and saves you a battle.
2–6 years — build the routine
Mineral SPF 30+ remains the easiest, but kid-formulated chemical filters are now considered safe. Always pair with: broad-brim hat, UV-blocking sunglasses (most kids' eyes filter less UV than adults'), and timing. Aim for outdoor play before 11 AM or after 4 PM during UV 6+ days. This is also the age to teach the "shadow rule" as a game.
6–12 years — autonomy and verification
School playgrounds in spring/summer routinely deliver UV 7–9 doses to bare arms and faces. Send kids out with sunscreen applied, a refillable stick in their bag, and a hat. Verify, don't trust: most kids forget reapplication. Outdoor sports clubs should have written sun policies; if yours doesn't, ask why.
How much sunscreen, exactly?
The classic "pea-sized blob" is way too little. For a 6-year-old, use about 15 ml total per full-body application — roughly the size of a golf ball. The breakdown:
| Zone | Amount |
|---|---|
| Face + neck + ears | 3 ml (1 teaspoon) |
| Each arm + hand | 2 ml |
| Chest + belly | 2 ml |
| Back | 2 ml |
| Each leg + foot | 2 ml |
The 5 mistakes parents make
- Trusting cloudy days. Up to 80 % of UV passes through clouds.
- One application for the whole pool day. Water, towels and sweat strip sunscreen in 40 minutes.
- Spray-only application. Sprays leave gaps; rub them in or use a stick on the face.
- Forgetting feet, ears, and the hairline. The most-burnt zones in pediatric clinics every summer.
- Sunglasses as accessory. Choose CE category 3+ with UV400 — most cheap kids' sunglasses block less UV than no sunglasses (pupils dilate behind the dark lens).
Special situations
Beach day
UPF 50 rash guard + mineral SPF on face/legs + wide-brim hat + parasol with a UPF cover. Reapply every 90 minutes, no exceptions.
Ski / snow
Snow reflects up to 80 % of UV — the dose at 1,800 m can match a tropical beach. Ski goggles (not sunglasses), zinc on cheeks and nose, lip balm with SPF.
Pool, lake
Water reflects ~10 % of UV and offers zero protection below the surface (UV-A penetrates 1 m of water). Reapply right after every swim.
Long car trip
Window glass blocks UV-B but lets ~60 % of UV-A through. Side-window UV film is cheap and protects the arm closest to the window.
Vitamin D and sun: don't overcorrect
Children also need vitamin D. The right balance, per WHO and most pediatric societies: 10–15 minutes of unprotected exposure on hands and forearms, two or three times a week, outside peak hours. For darker-skinned kids in northern latitudes, this is rarely enough — pediatric supplementation is the rule, not the exception, in winter.
Where Sun Day fits in
Sun Day lets you set family profiles for each child (Fitzpatrick skin type, age, current adaptation). The app calculates a burn timer per child from the live UV index at your location, sends a notification when it's time to reapply, and tells you the safe vitamin D window of the day. No ads, no data sold, no fake "UV sensor".
Protect every child, all year long
Add your kids to Sun Day and let the app do the math.