Product Code Database
Daylight is the combination of all direct and indirect sunlight during the daytime. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by Earth and terrestrial objects, like and buildings. Sunlight scattering or reflected by astronomical objects is generally not considered daylight. Therefore, daylight excludes moonlight, despite it being reflected indirect sunlight.
Outdoor illuminance varies from 120,000 lux for direct sunlight at noon, which may cause eye pain, to less than 5 lux for thick storm with the Sun at the horizon (even <1 lux for the most extreme case), which may make shadows from distant visible. It may be darker under unusual circumstances like a solar eclipse or very high levels of atmospheric particulates, which include smoke (see New England's Dark Day), dust, and volcanic ash.
| Brightest sunlight |
| Bright sunlight |
| AM 1.5 global solar spectrum sunlight (= 1,000.4 W/m2) |
| Shade illuminated by entire clear blue sky, midday |
| Typical overcast day, midday |
| Sunrise or sunset on a clear day (ambient illumination) |
| Extreme of thickest storm clouds, midday |
| Fully overcast, sunset/sunrise |
| Extreme of thickest storm clouds, sunset/rise |
For comparison, nighttime illuminance levels are:
| Moonlight, clear night sky |
| A full Moon, clear night sky |
| A lunar phase, clear night sky |
| Starlight, clear moonless night sky, including airglow |
| Starlight, clear moonless night sky, excluding airglow |
| Venus at brightest, clear night sky |
| Starlight, overcast moonless night sky |
For a table of approximate daylight intensity in the Solar System, see sunlight.
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