Sunsetter

Step 1 of 3

Choose where you’ll stand

Tap the map twice: first your viewpoint, then the horizon where you want the sun.

Sun alignment Two points reveal the dates

Open map data © OpenStreetMap. Tiles by OpenFreeMap.

How Sunsetter works

The instant the Sun meets the horizon

The Sun's lower limb touching the horizon An orange sun rests with its lower edge on a horizontal line. An arrow labels that contact point as the lower limb. horizon lower limb the Sun's lower edge
The “lower limb” is simply the bottom edge of the Sun.

We show the dates when that lower edge just touches the horizon along your chosen sightline. In the calculation, the Sun’s center is 0.25° above the geometric horizon.

This is an astronomical alignment. Local terrain, buildings, weather, and atmospheric effects can change what you actually see.