Sundog: Sun Exposure Tracker

• Circadian Reset - Morning light sets your body clock for the day. A short session before 9am resets your sleep-wake rhythm, lifts mood, and sharpens focus.
• Vitamin D - Midday UVB is your window. Sundog times your session to maximize D synthesis and stops automatically before you reach your burn limit.
• Gradual Tan - Afternoon light has lower UV intensity. Sundog schedules your exposure when the risk is lowest and the result is real.
• Sleep Optimization - Evening golden-hour light cues melatonin production, making it easier to fall asleep and stay asleep.

Smart, Not Just Simple

Sundog's timer isn't a countdown - it's a calibrated recommendation. It reads the live UV index and adjusts your session length automatically. Heavy cloud cover? Session extended. UV extreme? Pulled back. Your burn limit is always front and center.

Built Around Your Skin

Set your Fitzpatrick skin type once. Sundog uses it to calculate your personal burn limit at any UV level and adjust every session recommendation accordingly. Skin type I gets very different guidance from skin type V.

Time-Window Gating

Each goal has a scientifically appropriate time window. Circadian Reset is a morning-only session. Vitamin D is gated to the midday UVB window. Sleep Optimization surfaces in the evening. You always know whether your window is open, closing soon, or already passed for the day.

Sun Tracker

A visual emoji-based tracker shows your progress across the day - which sessions you've completed, which are still open, and what's coming up next.

Daily Sun Insights

Every day, Sundog surfaces a new insight - practical, evidence-based tips on UV, circadian biology, and getting more from your time outside.

Available in English and Spanish.

Sundog is designed for general wellness purposes only. It is not a medical device and does not provide medical advice. Consult a qualified healthcare professional before changing your sun exposure habits, particularly if you have a skin condition, a history of skin cancer, or are taking photosensitizing medications. UV exposure carries inherent risks. Always use appropriate sun protection.