Parhélie

ACTIVE

Find when another city sees your exact same sun

Launched July 28, 2026

About Parhélie

Parhélie is a web‑app that calculates the sun’s exact height for any city worldwide and determines the precise dates when another city experiences the same solar position. Users select a city, date and time and receive day‑level results with observatory‑grade accuracy (≈0.1°) using NOAA solar algorithms. It covers 7,774 cities with over 80 000 inhabitants across all continents, handling exact time zones and daylight‑saving automatically. The app is a one‑time purchase (0.99 €, no subscription), works on iPhone, Android and computers, and runs offline after being added to the home screen.

Pricing

Pricing information isn't available yet.

Capabilities

Exact sun position calculation

Uses NOAA solar algorithm to compute sun height with ~0.1° precision.

Match sun position between cities

Finds the exact date, day and hour when another city shares the same sun height as the selected location.

Solar event dates

Provides dates for zeniths, solstices and equinoxes for each city, including leap‑year handling.

Global city coverage

Supports 7,774 cities with populations over 80 000, covering all continents and exact time‑zone/DST adjustments.

Offline web‑app access

After purchase, the app runs in the browser and can be added to the home screen for use without an internet connection.

Cross‑platform availability

Works on iPhone, Android devices and desktop computers.

Use Cases

Expatriate home‑city comparison
Determine when the sky in a new city matches the sunlight of the user’s hometown.
For: People living away from their place of origin
Travel lighting planning
Select travel dates when the destination city offers desired sunlight conditions.
For: Travelers planning trips around seasonal light
Photographic lighting scouting
Find precise dates and times for optimal natural lighting in different locations.
For: Photographers
Educational solar phenomena teaching
Demonstrate solar positions, solstices and equinoxes across cities for classroom use.
For: Teachers and students
Curiosity‑driven sky exploration
Explore when and where the same sun appears, satisfying personal interest in astronomy.
For: General public and sky enthusiasts