On which day of the year is there exactly 12 hours of daylight and 12 hours of nighttime?
963687
There is no day of the year that has EXACTLY 12 hours of daylight and 12 hours of dark because no day is EXACTLY 24 hours long. A sidereal day is 23 hours, 56 minutes, 4.091 seconds long. On the equinoxes, we have approximately equal amounts of light and dark.
956732
you are right,lenght of day depends on : date (position of the earth on it's orbit); location on earth (latitude, elevation);  to calculate day/night lenght, longitude is needed only to find mean time of sunrise/set,noon...in calculs, time should be converted to UTM, dates to Julianian dates.\ni don't know formula to calculate length of day/night,but here's some usefull sites:\nhttp://www.gcstudio.com/suncalc.html\nhttp://susdesign.com/sunangle/\nhttp://aa.usno.navy.mil/faq/docs/equinoxes.html
262935
12 midnight is technically 12 AM.
217739
I dont know.  How did the english get the world to go along with it?  Also why not have 12 hours of light and 12 hours of dark.  Instead they do 6am is sunrise.  Why not 1am sunrise and 1pm sunset.
248009
12 AM (midnight) to 12 PM (noon): Morning.\n12 PM to 6 PM: Afternoon.\n6 PM to 12 AM: Evening.
616447
British summer time officially begins: on the last weekend in March where the clocks go forward and the days are brighter and longer. The longest daytime in the year is mid June where the sunsets around 10.30 - 11.00 at night.\nBritish summer time officially ends: on the last weekend in october when the clocks go back and the nights begin to get darker and darker.
780566
0.1 a minute 24-7-365\n\nyou know it is a big world out there with a lot of people and it is always day light some where
1091939
Like night and day, the northern half of the planet has the opposite season from the southern half. And along the equitor there's really not much season at all!\n\nOn the other side of the planet from you (east and west)  it's 12 hours difference in time, yes? So if it's noon where you are then it's midnight there.\n\nAnd on the opposite side of the planet from you (north and south) the weather is like six months difference ... middle of the summer for you is middle of the winter there.\n\nIt's all about where the sun is, as earth spins (day/night) and orbits around (summer/winter).
976691
Many more than 24. The Microsoft Windows clock lists 75. \n\nYou must consider that some countries observe solar time. Some countries have time zones that are 30 minutes or even 15 minutes off of the rest of the world's hours. The southern hemisphere observes "daylight savings" or "summer" time during different months than the northern hemisphere.
796172
Equinox means equal night......the two days a year ( March and September) when the sun at noon is directly overhead at the Equator. The two solstices are Summer when the sun is directly overhead at 23N and the Winter when its directly overhead at 23S...so your shadow would point south everyday of the year at 23S except on the Winter Solstice when there would be, in theory, no shadow at all since the sun is 90 degrees overhead
614867
Monday:\n\nIn a leap year there are 366 days.  So 12/31 will be *365* days later than 1/1, not counting the original day.  (This is for a leap year.  In a non-leap year there are 364 days between 1/1 and 12/31).\n\nIf you take 365 and divide by 7 you get 52 r. 1, meaning there are 52 weeks and 1 day.  So 12/31 will be one day later.\n\nIf leap year begins on a Sunday, December 31 in that same year will be a Monday.  If you mean the day before (December 31 of the prior year) the answer is Saturday :-)
1041232
An equinox in astronomy is the moment when the Sun passes over the equator. The event occurs twice a year, around March 20 and September 23. The word equinox derives from the Latin word for equal night. The equinoxes are the two days each year when the middle of the Sun is an equal amount of time above and below the horizon for every location on Earth.
1091516
~Trick question.  At what time on what day of what year?
212651
365.256366 Earth days around the Sun, if that's what you mean. Or 24 hours around its axis.
11643
All days are the same length, but in the northern hemisphere, December 21st has the shortest amount of day light.  June 21st in the southern hemisphere.
191575
must be Alaska right?? I think it's 6 months of daylight and 6 months of night over there... :o)
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.