International Date Line International Date Line The International Date Line (IDL) is an imaginary line of demarcation on the surface of Earth that runs from the North Pole to the South Pole and demarcates the change of one calendar day to the next. It passes through the middle of the Pacific Ocean, roughly following the 180° line of longitude but deviating to pass around some territories and island groups. The IDL is roughly based on the meridian of 180° longitude, roughly down the middle of the Pacific Ocean, and halfway around the world from the Greenwich meridian. In many places, the IDL follows
Comox Land District along that latitude west, with some minor variances around land parcels to 50 degrees 0 minutes north latitude at 125 degrees 41 minutes 8 seconds west longitude, then south along that longitude to 49 degrees 54 minutes 29 seconds north latitude, then west along that latitude to 125 degrees 45 minutes 58 seconds west longitude, then via a straight diagonal line southeast to 49 degrees 37 minutes 31 seconds north latitude at 125 degrees 24 minutes 17 seconds west longitude, then east to 125 degrees 0 minutes 9 seconds west longitude, just west of the town of Cumberland and north