Solar Day

Sparrow Hill

In-app purchases

About this app

Solar Day

Solar Day is a clean, privacy-first app for understanding today’s daylight hours and your position in the solar year.

Designed for people who rely on natural light — whether for solar energy systems, off-grid living, photovoltaic power, battery charging, or personal wellbeing — Solar Day provides a clear view of sunrise, sunset, solar angle, and seasonal change.

Free Version

• Daylight duration
• Sunrise and sunset (local time)
• Seasonal solar year graphic
• Days to next solstice
• 7-day daylight change
• Manual location entry or GPS

Solar Day helps you build real intuition about daily and seasonal sunlight patterns — without notifications, accounts, or distractions.

SolarDay Pro (One-Time Upgrade)

SolarDay Pro adds deeper solar energy context and planning tools:

• Solar Effectiveness (5-level indicator)
Negligible • Poor • Moderate • Good • Excellent
Combines seasonal solar inclination with atmospheric conditions
(cloud cover and haze reduce — but never increase — the seasonal baseline)

• Effective Sun Hours
• Effective Sun Window
• 3-Day Cloud Cover Outlook
• Solar Inclination Graphic (visual sun angle)
• Contextual seasonal guidance

No subscriptions. One purchase. Lifetime unlock.

Payments are securely handled by Google Play.

Privacy

Solar Day is built with respect for users.

• No accounts
• No ads
• No analytics
• No tracking

Core solar calculations run entirely on your device.

If you use SolarDay Pro, cloud cover data is retrieved from a public weather service to provide short-term atmospheric context. No personal data is collected, stored, or sold.

Solar Day is developed by Sparrow Hill — thoughtful tools built with clarity and restraint.

What’s new

Initial release of SolarDay
Privacy-focused solar awareness app
Understand daylight, solar angle, and seasonal progression