How do the seasons change and why do we lose so much daylight during the month of September? It’s all tied to Earth’s tilt on its axis. The amount of daylight is directly tied to seasonal changes, and this is caused by the tilt of Earth's axis. As our planet revolves around the sun, its 23.5-degree axial tilt means that different hemispheres receive varying amounts of direct sunlight throughout the year. The northern hemisphere receives less exposure to sunlight through fall into winter, resulting in shorter daylight hours. At the winter solstice (around December 21), this effect peaks, resulting in the shortest day of the year! #seasons #september #daylight #sunlight #seasonchange