environmental condition subpolar boreal envoPolar ORCID:0000-0002-4366-3088 2013-09-04T07:08:34Z subarctic Note that this class refers to a climatic rather than a positional condition. A subpolar condition is an environmental condition in which an environmental system receives low, yearly solar irradiance per unit area and is surrounded by large land masses. This results in very cold winters with temperatures potentially falling to around -40 degrees Celsius and summers which last no more than 3 months of the year with a 24-hour average temperature of at least 10 degrees Celsius.