The observance of Halacha in the polar regions of Earth presents unique problems, since many Mitzvos are dependent on the cycle of day and night in 24-hour periods. However, in the polar regions a single period of daylight can last for a month or more during the summer, and the night lasts for a similar length of time in the winter.  This choveres discusses the various opinions in the poskim how does one reconcile the observed length of days in the polar regions with common practice elsewhere in the world.