At some point in the distant past , Planetos had normal seasons . The something happened which threw them out of whack . Each season lasts for one or more years , but there are no exact , official dividing lines as in our world . The seasons are the same all over the world , but different regions are affected to different extents . Dorne , for example , has much milder winters than the North due to being much closer to the equator . One solstice or equinox occurs each season . When the summer solstice is observed , it means that winter is on its way and it ' s time to start setting food aside . North of the Wall , yes , winter means several years of permanent darkness . Other lands get some measure of sunlight , but during the years of winter the days are still shorter than the nights . As on Earth , seasons on Westeros are reversed in the southern hemisphere .