Spring, also referred to as springtime, is one of the four temperate seasons (winter, spring, summer, fall). Spring occurs between winter and summer. It is often associated with the themes of life, rebirth, renewal, regrowth, etc. because it is a period during which snow melts, the temperature increases, many animals are born, and many plants begin growing again after winter.
Based on the meteorogical definition of spring, spring occurs from March 1st through May 31st in the Northern Hemisphere and September 1st through November 30th in the Southern Hemisphere.
What causes spring?
Spring, as well as the rest of the temperate seasons, are caused by the tilt of the axis of rotation of Earth relative to that of the plane formed by its orbit around the Sun. Because of this tilt, the different regions of Earth experience varying amounts of sunlight throughout the year, leading to the four seasons in temperate regions. Below is a depiction of the tilt of the earth relative to its orbital plane.
Because the Northern Hemisphere and Southern Hemisphere are on opposite ends of the Earth, they experience the seasons at opposite times. When it is spring in the Northern Hemisphere, it is fall in the Southern Hemisphere. Likewise, when it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere.
Regions closer to the Equator do not experience the four seasons. Rather, they experience a wet and dry season. During the wet season, tropical regions experience most of their average annual rainfall. The reason that tropical regions do not experience the four seasons is because the amount of sunlight does not vary much throughout the year in these regions.