Glossary
The English version of our glossary is currently under construction and will be regularly updated.
10 °C isotherm
The 10 °C isotherm is an imaginary line connecting all points with a mean temperature of less than 10 °C in high summer.
The Arctic is typically defined as the region within (i.e., to the north of) the Arctic Circle at 66° 30’ N. The parallel defines the borders within which the Midnight Sun can be seen. Another definition of the Arctic is the region bordered by the 10 °C isotherm. The 10 °C isotherm is an imaginary line connecting all points with a mean temperature of less than 10 °C in high summer. It also roughly equates to the northern tree line.