UV Index: Sun & Vitamin D

Track real-time UV rays, calculate your safe sun exposure time, and get personalized sunburn alerts for your skin type — all in one place. The only UV index app that tells you exactly when the sun helps and when it harms.

Recommended for people with vitamin D deficiency looking to safely increase sun exposure, outdoor athletes, and anyone protecting fair or sensitive skin.

★ LIVE UV INDEX & FORECAST ★

• Real-time UV index and UVA/UVB levels for your exact location

• Hour-by-hour UV forecast from sunrise to sunset

• Full 7-day UV outlook with daily highs

• Color-coded UV scale (low, moderate, high, very high, extreme) following the WHO standard

• Background that adapts to current UV intensity

★ VITAMIN D TIMER ★

Stop guessing how long to stay outside. The vitamin D timer calculates your exact minutes of sun exposure to reach the ~1,000 IU daily reference intake, personalized to:

• Your Fitzpatrick skin type (I–VI)

• Current UV index at your location

• Sun elevation and time of day

• Bare-skin assumption (face, arms, legs)

When the timer ends, extra sun adds little vitamin D and only raises your burn risk — clear, science-based guidance you can trust.

★ SUNBURN CALCULATOR & SKIN CANCER PREVENTION ★

• Sunburn time estimate — minutes until your skin reaches its minimal erythemal dose (MED)

• Personalized to your phototype — fair skin gets stricter limits than tanned skin

• SPF reminder when you push past your safe window

• Daily UV warnings to avoid the riskiest hours

• Supports responsible skin cancer prevention habits with data, not guesswork

★ VITAMIN D NOTIFICATIONS ★

Never miss the best moment for sun-derived vitamin D. Pick the alerts you want:

• Window opens — when UV first reaches the synthesis threshold today

• Best moment of the day — peak UVB intensity, your shortest dose

• Last chance — final viable hour for vitamin D before the sun drops

★ SKIN TYPE PERSONALIZATION ★

Pick your Fitzpatrick phototype once and every calculation adapts automatically. From Type I (always burns, never tans) to Type VI (deeply pigmented). The same UV index means very different things for different skin — UV Index: Sun & Vitamin D respects that.

★ WHY UV INDEX BEATS A BASIC WEATHER APP ★

Most weather apps show a UV number and nothing else. UV Index: Sun & Vitamin D translates that data into the two outcomes that actually matter: vitamin D in, sunburn out. Whether you're planning a beach day, a long run, gardening, or walking the dog, you'll know exactly when the sun helps and when it harms.

★ THE SCIENCE ★

Built on peer-reviewed dermatology and atmospheric research:

• WHO / ICNIRP UV index scale

• Fitzpatrick skin classification (AAD)

• AEDV 2020 vitamin D / MED exposure ratios

• Webb (1988) solar elevation thresholds for cutaneous synthesis

• Holick (1981) previtamin D3 photoequilibrium

We don't approximate by region or season — your local weather forecast already encodes ozone, altitude, and cloud cover.

★ PRIVACY-FIRST ★

• Location used only to fetch weather data — never stored or shared

• No tracking, no profile selling

• Skin type and settings stored locally on your device

★ PERFECT FOR ★

✓ Outdoor enthusiasts — runners, cyclists, hikers, climbers

✓ Beach lovers, surfers, swimmers, sailors

✓ Parents protecting children's sensitive skin

✓ Anyone correcting low vitamin D or vitamin D deficiency

✓ Fair-skin and sensitive-skin users (Fitzpatrick I & II)

✓ Drivers, gardeners, and outdoor workers

✓ Travelers comparing UV index between destinations

Whether you call it a UV index forecast, sunburn calculator, sun exposure tracker, vitamin D timer, or simply your sun safety app — UV Index: Sun & Vitamin D gives you everything in one clean, fast experience.

Download today and get the most out of every sunny day — safely.