why is the number of hours of daylight greater in summer then in winter?
450708
I guess it's time someone writes down a correct answer...\n\nThe earth rotate on its axis, which runs through the north and south poles.  It so happens that the earth's axis is not perfectly vertical.  Because the axis is at an angle, we spend half the year (it changes during the equinox) with the north pole (and hence the northern hemisphere) tilted towards the sun - this is summer.  We spend the other half of the year with the south pole tilted towards the sun (hence, the northern hemisphere is tilted away from the sun) - this is the winter.  Now I will leave it up to you to think about why this should make the summer days longer than the winter days.  Try this:  grab a basketball (better yet, a globe), turn off all the lights, point a flashlight at it and spin it with the axis rotated towards the light and with the axis rotated away from the light.  Follow a single point on the top half of the ball and see if you can make sense why this point stays in the light longer when the axis is pointed towards the light versus when the axis is pointed away from the light... \n\nIt's a nice point to make that in the southern hemisphere (Australia, Chile, South Africa, etc.) the days are longer in the winter and shorter in the summer.  If you think for a moment, it shouldn't be too hard to figure out why...
287541
When they start has to do with the length of days.  The first day of Summer is the longest (by daylight) day of the year.  Winter is the shortest.  Fall and Spring are when the two lengths are equal.
537266
The sun actually doesn`t change position, it`s the tilt of the earth that makes it look like it is changing position. When the earth is tilted towards the sun we get more daylight hours (summer), when the earth is tilted away from the sun we get less daylight hours (winter). But we are not warmer cos we are closer to the sun, we are warmer because the angle to the sun is closer to 90 degrees in summer than in winter. If in northern hemisphere then the sun will always be at least a little to the south (even in summer).
25923
The official time is adjusted forward, (usually) one hour from its official standard time, remaining that way for the duration of the spring and summer months. This is intended to provide a better match between the hours of daylight and the active hours of work and school. DST is most commonly used in temperate regions, due to the considerable variation in the amount of daylight versus darkness through the seasons in those regions.
667963
It's polar night in winter when the sun is sufficiently below the horizon, so that there is insufficient sunlight or no light at all. (A lingering dusk may occur, if the sun is only 12 degrees or less below the horizon.) \n\nA common misunderstanding is that at each point inside the polar circle the shortest day is totally dark. Because of twilight, this is not the case.\n\nSince the earth's axis is tilted with respect to the ecliptic by approximately 23 degrees 26 minutes (commonly rounded to 23 degrees and a half), the sun does not set at high latitudes in (local) summer. The duration of the midnight sun increases from one day during the summer solstice at the polar circle to approximately six months at the poles. At extreme latitudes, it is usually referred to as polar day. The length of the time when the sun is above the horizon varies from 20 hours at the Arctic Circle and Antarctic Circle to 186 days at the poles.
418252
There is a very common myth that it has something to do with farmers, but it is actually and energy conservation measure.  The whole idea was originally a big joke made by Benjamin Franklin.  Not all States in the Union do DST, nor do all Counties in every State.\n\nInterestingly enough, in these days of ubiquitous air conditioning, there may be no cost savings in lighting as was originally intended.\n\nThe reality is that the "Spring Forward" portion of DST causes additional traffic fatalities.  It is a dangerous practice that is continued thanks to governmental inertia and constituent apathy.
1130548
Winter Solstice has the least daylight: Dec 21. March 21 and September 21 are the vernal and autumnal equinoxes (when day = night = 12 hours). June 21 = the day with most daylight (in Northern Hemisphere).
1001738
Please also remember that while the Earth rotates at constant speed, it does not *orbit* the sun in a circular orbit, rather an ellipse.\n\nTherefore, during one part of Earth's journey around the sun the Earth spends less time while orbiting closer to the sun than when farther away.  This would mean that the Earth spent slightly less than 6 months in that section, and slightly more than 6 months when orbiting farther away from the sun.\n\nThe answer to your question is, no, not all points receive the exact same amount of daylight in one year, but the difference is small.
534312
In the spring and summer months when the weather patterns are unstable.  The second answer would be at night.
497349
Daylight saving time (DST), also known as summer time and sometimes referred to (some think erroneously - see later) as daylight savings time, is a widely used system of adjusting the official local time forward, usually by one hour, from its official standard time for the summer months. This is intended to provide a better match between the hours of daylight and the active hours of work and school. The "saved" daylight is spent on evening activities which get more daylight, rather than being "wasted" while people sleep past dawn.\n\nDST is most commonly used in temperate regions, due to the considerable variation in the amount of daylight versus darkness across the seasons in those regions.\n\nGovernments often tout it as an energy conservation measure, on the grounds that it allows more effective use of natural sunlight resource in summer time. Since there is less darkness in the "waking day", there is less use of electric lights. Some opponents reject this argument (see below, Criticism).\n\nEuropeans commonly refer to the system as summer time: Irish Summer Time, British Summer Time, and European Summer Time. This is reflected in the time zones names as well, e.g., Central European Time (CET) becomes Central European Summer Time (CEST).\n\nThe word "summer" in this context includes most of spring after the spring equinox and nearly all of autumn (April through October). Likewise, the word "winter" here includes part of autumn and a few weeks in spring (November through March). This varies by time zone, of course, and can change over time as well.
3243
From wikipedia:\n"Daylight saving time (also called DST) is the North American term for a system intended to "save" daylight (the British observe summer time, and likewise the Europeans). The official time is adjusted forward, (usually) one hour from its official standard time, remaining that way for the duration of the spring and summer months. This is intended to provide a better match between the hours of daylight and the active hours of work and school."\n\nIn my own wordings, it's adjusting time in summer/winter so you won't be going to school/work when it's dark, or waking up at 6am and the sun is too high in the sky.\nCountries usually adjust the time to make the change between summer/winter in sunrise/sunset easier on people.
1138253
In the Northern hemisphere, the "Winter" solstice is on December 21. It is the "Summer solstice that occurs on June 21st. In the southern hemisphere, the opposite is true.\nThe change in the amount of daylight is very small for the first few weeks, but as we approach the next solstice the change increases up to about 9 minutes a day.
1179944
it is strongest between 10am and 2pm.  this is because as the sun rises from the horision the light (and other radiations) are being filtered through more atmosphere. as the sun climbs higher it is comming more directly at you, peeking at noon(ish). Finally as the sun sets it reverses the process and again becomes filtered through more atmosphere.
1136622
Going from winter to summer, the length of the day and night changes a lot in countries that are far away from the equator.  These countries need to change their time in order to save on their electricity bills.\n\nBut in countries that are close to the equator, the length of the day and night doesn't change much during the year.  And there is no advantage for them to change their time.\n\nWhen you live right on the equator, then the length of your day and night are always 12 hours exactly throughout the year.
243543
It was invented during world war 2 to increase production. It was called "war time". Basically instead of keeping to one time frame it has you start your day earlier in the summer and the "normal" time it would start in the winter by one hour. The idea was that if someone got to work earlier in the summer they would hopefully stay a little later since there was still daylight. It helped production by %5-10.
391070
I love daylight sayings time because it allows me to work longer hours during the spring and summer months when my business is real busy. The swimming pool biz. I can also work until 7 or 7:30 and still have an hour or an hour and a half of daylight when I get home. It also makes the weekends and days off longer to spend at the lake or river or where ever you are outdoors.
75399
The reason there is differing amounts of daylight is that the Earth's axis is tilted with respect to the plane of its rotation about the sun. When the north pole is tilted towards the sun, the northern hemisphere days get longer. The point in the Earth's orbit about the sun where the plane through the Earth's axis that is perpendicular to the Earth's plane of orbit ALSO passes through the sun itself (i.e. the Earth's rotation axis is lined up with the sun, north end closest) is the summer solstice. When the same plane passes through the sun again, only with the south pole closest, that is the winter solstice. At summer solstice, the length of the day is longest in the northern hemisphere. At winter solstice the day is shortest in the northern hemisphere. The opposite is true in the southern hemisphere. On the equator the lengths of the days don't change at all! The further you get from the equator, the more the length of the days change with the seasons.\n\nSo let's talk northern hemisphere. If the longest day is around June 21 (summer solstice) and the shortest day is Dec 21 winter solstice, you can think of the length of the days as changing smoothly from shortest to longest as you move from winter to summer solstice. If you do the geometry to figure out how the length of days changes with the seasons, it looks a lot like a sine wave. It's actually shaped a little differently because the Earth's orbit is not a circle--that would make a sine wave exactly for the length of days--but instead an ellipse. But it's still pretty close to a sine wave. If you look at a sine wave, you'll notice that as the wave approaches the bottom, slows down its descent until it almost "flattens" at the bottom, but not quite. Then after the bottom, it goes up more steeply until somewhere in the spring it is changing as fast as possible (pretty near to the vernal equinox), then begins to slow down again until it hits the peak at the summer solstice. After the summer solstice, the longest day, the length of days begins to fall, slowly at first and then ever faster, until somewhere in fall (pretty near the autumnal equinox) it's changing as fast as it's ever going to. Then it begins to slow down, until it hits the minimum at the winter solstice again. If you look back at the description about, you'll notice that the rate at which the length of days change also varies with the season. In fact, the rate of change is like a sine wave, too, only it's shifted by a season from the wave that describes the rising and falling of the length of the day itself.\n\n\nFor the latitudes farther away from the equator, the amplitude of the sine wave is larger. For the southern hemisphere it is flipped upside down compared to the same latitude in the northern hemisphere. And on the equator, the "sine" curve as zero amplitude--that is, it's a straight line.\n\nIn calculus you would say that the rate of change of a function (the "derivative" of the function with respect to time) tells you how fast the daylight is changing on a given day. And, in calculus you also learn that the rate of change of a sine wave is a cosine wave--or just another sine wave shifted back by 90 degrees. And 90 degrees of the sine wave describing the length of days corresponds to one season on Earth!