Daylight is the combination of all direct and indirect sunlight
Sunlight is a portion of the given off by the , in particular , , and light. On , sunlight is and through , and is obvious as when the Sun is above the . When direct is not blocked by s, it is experienced as sunshine, a combination of b ...
during the daytime
On Earth, daytime is the period of the day during which a given location experiences Daylight, natural illumination from direct sunlight. Daytime occurs when the Sun appears above the local horizon, that is, anywhere on the globe's Hemisphere ...
. This includes direct sunlight
Sunlight is a portion of the given off by the , in particular , , and light. On , sunlight is and through , and is obvious as when the Sun is above the . When direct is not blocked by s, it is experienced as sunshine, a combination of b ...
, diffuse sky radiation
upright=1.9, The visible spectrum, about 380 to about 740 nanometers (nm), shows the atmospheric water absorption band and the solar Fraunhofer lines. The blue sky spectrum presents across 450–485 nm, the wavelengths of the color blue.
Diff ...
, and (often) both of these reflected by Earth
Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% is Water distribution on Earth, covered wi ...
and terrestrial objects, like landform
A landform is a natural or artificial feature of the solid surface of the Earth or other planetary body
A planet is an astronomical body
Astronomy (from el, ἀστρονομία, literally meaning the science that studies the laws ...
s and buildings. Sunlight or reflected by 
astronomical object
In astronomy, an astronomical object or celestial object is a naturally occurring physical object, physical entity, association, or structure that exists in the observable universe. In astronomy, the terms ''object'' and ''body'' are often us ...
s is generally not considered daylight. Thus, daylight excludes moonlight
Moonlight consists of mostly (with little ) reflected from the parts of the surface where the light strikes.
Illumination
The intensity of moonlight varies greatly depending on the , but even the typically provides only about 0.05–0.1&nbs ...
, despite it being reflected indirect sunlight.
Definition
Daylight is present at a particular location, to some degree, whenever theSun
The Sun is the star
A star is an astronomical object consisting of a luminous spheroid of plasma (physics), plasma held together by its own gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many othe ...
is above the local horizon
The horizon is the apparent line that separates the surface of a celestial body
In astronomy
Astronomy (from el, ἀστρονομία, literally meaning the science that studies the laws of the stars) is a natural science that st ...
. (This is true for slightly more than 50% of the Earth
Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% is Water distribution on Earth, covered wi ...
at any given time. For an explanation of why it is not exactly half, see here
Here is an adverb that means "in, on, or at this place". It may also refer to:
Software
* Here Technologies, a mapping company
* Here WeGo (formerly Here Maps), a mobile app and map website by Here
Television
* Here TV
Here TV is an America ...
). However, the outdoor illuminance
In photometryPhotometry can refer to:
* Photometry (optics), the science of measurement of visible light in terms of its perceived brightness to human vision
* Photometry (astronomy), the measurement of the flux or intensity of an astronomical ob ...
can vary from 120,000 lux
The lux (symbol: lx) is the SI derived unit
SI derived units are units of measurement
'
Measurement is the number, numerical quantification (science), quantification of the variable and attribute (research), attributes of an object or event, wh ...
for direct sunlight
Sunlight is a portion of the given off by the , in particular , , and light. On , sunlight is and through , and is obvious as when the Sun is above the . When direct is not blocked by s, it is experienced as sunshine, a combination of b ...
at noon
Noon (or midday) is 12 o'clock
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. (from Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the In ...
, which may cause eye pain
Pain is a distressing feeling often caused by intense or damaging stimuli. The defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage." In medical ...
, to less than 5 lux
The lux (symbol: lx) is the SI derived unit
SI derived units are units of measurement
'
Measurement is the number, numerical quantification (science), quantification of the variable and attribute (research), attributes of an object or event, wh ...
for thick storm cloud
In meteorology, a cloud is an aerosol consisting of a visible mass of minute liquid drop (liquid), droplets, ice crystals, frozen crystals, or other particulates, particles suspended in the atmosphere of a planetary body or similar space. Wate ...
s with the Sun at the horizon (even <1 lux for the most extreme case), which may make shadows from distant street light
A street light, light pole, lamppost, street lamp, light standard, or lamp standard is a raised source of light on the edge of a road or path. Similar lights may be found on a railway platform. When urban electric power distribution became ubiqu ...
s visible. It may be darker under unusual circumstances like a solar eclipse
A solar eclipse occurs when a portion of the Earth
Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The re ...
or very high levels of atmospheric particulates
Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM), or suspended particulate matter (SPM) – are microscopic
The microscopic scale (from , ''mikrós'', "small" and σκοπ ...
, which include smoke (see New England's Dark Day
New England's Dark Day occurred on May 19, 1780, when an unusual darkening of the daytime sky was observed over the New England
New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusett ...
), dust, and volcanic ash.
Intensity in different conditions
For comparison, nighttime illuminance levels are: For a table of approximate daylight intensity in theSolar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...
, see sunlight
Sunlight is a portion of the given off by the , in particular , , and light. On , sunlight is and through , and is obvious as when the Sun is above the . When direct is not blocked by s, it is experienced as sunshine, a combination of b ...
.
See also
References
External links
Daylight Chart
shows sunrise and sunset times in a chart, for any location in the world
Length of Day and Twilight – Deriving the formulas to calculate the length of day
Daylight vs Artificial Light
{{Authority control Atmospheric optical phenomena Light Parts of a day Visibility