Of course, the way things are going, extreme-heat resistance is probably going to be more valuable than cold resistance.
Literally: year-end – cold – pine tree – cypress tree
Alternately: Seeing one’s convictions through even when times are bad. Perseverance in adversity.
Notes: This is a compound of compounds; 歳寒 refers to winter (and by extension, harsh or difficult conditions), while 松 and 柏 refer to evergreen trees – that maintain their color and cover even when other trees have dropped their leaves for the winter. Note that in Japanese 柏 often refers to the “Japanese emperor oak,” but context makes it clear here that the character is referring to an evergreen, the “Chinese arborvitae.” Incidentally, the compound 松柏 seems to be commonly associated with bonsai in modern Japanese.
This phrase comes to us from our old friend, the Analects of Confucius (Japanese 『論語』 = Rongo). In some cases the reading of two halves of the phrase may be separated with a no (as in associative particle の), but has no effect on how the four-character compound is written.
A similar compound is 雪中松柏 (secchuu shouhaku), “pine and cypress amidst the snow,” although this refers more precisely to someone who holds fast to their convictions instead of changing according to what is popular or convenient at the time. See also 志操堅固.