Hover the map to see the Sun's altitude and the local solar time anywhere. Click to mark a place.
At every moment there is one point on Earth where the Sun is straight overhead (the sub-solar point). Everywhere within 90° of it is in daylight. The edge of that region is the terminator, and the bands beyond it are civil, nautical and astronomical twilight, where the Sun is up to 6°, 12° and 18° below the horizon.
Around the equinoxes the terminator runs north–south and every place gets about 12 hours of daylight. Near the solstices it tilts by 23.4°, giving midnight sun on one polar cap and polar night on the other.
Sun positions use the NOAA formulas; the Moon uses the astronomy-engine library, bundled with the page. Nothing is downloaded while you use it.