If you live up here, in summer the sun is coming fairly directly down, but in winter it's coming through a huge amount of atmosphere, and much of the ultraviolet is weeded out, and the range of wavelengths that hit the Earth are different from summer to winter.
Živimo li ovdje, ljeti sunce pada prilično izravno, ali zimi se probija kroz ogromne slojeve atmosfere, i mnogo se ultraljubičastih zraka gubi, a raspon valnih duljina koje dolaze do Zemlje se od ljeta do zime razlikuje.