TIme of darkness depends on three things:

1) How far North or South you are--the closer to the North or South pole, the greater the seasonal change between summer and winter. (Above the Arctic Circle and below the Antarctic circle, the day length [in summer] and night length [in winter] get so long they exceed 24 hours!).

2) The Season--days are longest/shortest at the Solstices (Dec. 21/June 21) and even (12 hours, no matter where on earth you are) at the Equinoxes (Sept. 21, March 21). Summer/Winter reverse between the Northern/Southern hemispheres; I'm not labelling any of these dates with Summer or Winter, because Mudcatters in the USA and Australia would disagree about which was which.

3) Where you are in relation to the center of your time zone. If you are on the Eastern edge of your time zone (e.g. Bangor [Maine] or Chicago), both sunrise and sunset will be early compared to points to your West. If you are at the Western edge (e.g. Columbus [Ohio] or Pierre [South Dakota], sunrise and sunset will be relatively late, no matter what the season.

--Charlie Baum