The smart, simple way to get enough sun without burning.

HELLO SUN

Real-time vitamin D estimates and sun + supplement tracking, with conservative burn-risk guidance. Personalized to your skin type and location. No ads. No data selling.

Safety & Privacy First • Weekly Status • Acclimation

Hello Sun session timer screen showing UV index, goal progress, and burn-safe session controls

Know Your Burn Time

Start a session and see a conservative burn countdown that adapts to your skin, UV, coverage, and SPF so you can get vitamin D and keep your skin safe.

Catch The Best Window

See the best times of day to go out when UV is effective but not extreme so you can plan a quick session instead of rolling the dice.

Hello Sun planner screen showing UV forecast graph and best window for safe sun exposure
Hello Sun progress screen showing weekly vitamin D chart, sun style insight, and achievements

Track your Progress

Vitamin D works more like a bucket than a daily meter. Hello Sun shows 7 day momentum so you can spot what’s working and adjust without perfection pressure.

Adapts to your skin

Your tolerance changes with seasons and habits. Hello Sun gradually adjusts safe limits based on your history. If you mark a burn, it switches into a gentler recovery mode for a few days.

Hello Sun app showing Recovery Mode info and an acclimation percentage chart over time
Hello Sun app progress dashboard showing sun points, levels, and weekly consistency metrics

Lifetime Progress Insights

See long term trends like momentum, consistency, and history so you can build a sustainable rhythm without chasing max exposure.

Low UV? Stay on track

When UV is too low for meaningful vitamin D, Hello Sun helps you pivot. Plan smarter, lean on supplements, and keep weekly momentum through low sun seasons.

Hello Sun winter mode screen showing vitamin D total, goal progress, and supplement logging

Safety-first sunshine, built on trust.

Conservative guidance. Privacy first by default. Designed for real life, including quick sessions, messy weeks, and changing seasons.

Estimates are guidance, not medical advice.

© Hello Sun 2026 • [email protected]