The Earth's axis of rotation is tilted art 23.5? to the perpendicular. This means that the amount of sunlight a particularly latitude receives changes with seasons. From April to September, the Northern Hemisphere is tilted towards the Sun, and consequently receives more energy. During October to March, the Southern Hemisphere is tiled towards the Sun, and summer in the Southern Hemisphere occurs at this time. During the Northern Hemisphere summer, the North Pole receives 24 hours daylight, whilst the South Pole experiences 24 hours darkness. During the other half of the year, the reverse is true. Despite the six months of continuous sunlight however, temperature at the poles remains low rarely rising above freezing because the Sun is never more than 23.5? above the horizon.