Elevation
—
degrees above the horizon — 0° is sunrise or sunset, 90° is directly overhead
Loading the selected sky.
- Visible light—
- UVA—
- UVB—
Where the sun is
The sun's angle above the horizon at this moment, and what that angle puts in the light reaching you.
Sun through the day
How the angle moves from sunrise to sunset, and which hours actually carry vitamin D and sunburn.
What to look for The black line is the sun's height through the day, read against the scale on the left. The two bars underneath show what that height delivers: when vitamin D can be made, and when you can burn. Stronger colour means more of it. Notice that the sunburn bar starts earlier and finishes later than the vitamin D bar — the shaded columns are those hours, when you can still burn and synthesis has already stopped.
- Sun's angle exact
- Vitamin D available modelled
- Sunburn possible modelled
The background colour is the sun's own colour at that height, and each band means something different for the light reaching you:
Every day of the year
The same reading repeated for all 365 days, at any latitude — where the vitamin D window opens, and where it closes.
What to look for Every row is one day of the year, top to bottom; every column is one hour, midnight to midnight. Each cell is coloured by how high the sun is at that moment. The dashed line rings the region where enough UVB reaches the ground for vitamin D synthesis to run. Drag the latitude slider upward and watch that region close: past roughly 37° a hole opens through the middle of the year — months during which the sun never climbs high enough, on any day, at any hour.
Your day in words
A plain-text summary of the selected day, written for the skin type you pick below.