Wiktionary
a. Pertaining to a region in the Southern Hemisphere immediately north of Antarctica and covering the many islands of the southern parts of the Indian Ocean, Atlantic Ocean and Pacific Ocean, which are north of the http://en.wikipedia.org/wiki/Antarctic%20Convergence.
Wikipedia
The Subantarctic is a region in the southern hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° – 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Indian Ocean, Atlantic Ocean and Pacific Ocean, especially those situated north of the Antarctic Convergence. Subantarctic glaciers are, by definition, located on islands within the subantarctic region. All glaciers located on the continent of Antarctica are by definition considered to be Antarctic glaciers.
Usage examples of "subantarctic".
Low cedars with black needles, a variety impervious to frosts that had been developed for the subantarctic regions, sang solemnly and monotonously in the never-slackening wind.
Polynesian food production depended mainly on agriculture, which was impossible at subantarctic latitudes because all Polynesian crops were tropical ones initially domesticated outside Polynesia and brought in by colonists.