Spring begins in the northern hemisphere around the months of March, April, May, or as reckoned astronomically extending from the vernal equinox. As in summer, the axis of the Earth is tilted toward the Sun and the length of daylight rapidly increases. The northern hemisphere begins to warm significantly causing new plant growth to "spring forth,"
The seasons are considered by some Western countries to start at the equinoxes and solstices, based on astronomical reckoning. In North American-printed English-language calendars, based on astronomy,
Today, the meteorological reckoning of the seasons is used in Australia, Denmark, the former USSR and by many people in the United Kingdom, but the astronomical definition is still more frequently used in the United States.
Autumn (also known as fall in North American English) is one of the four temperate seasons. Autumn marks the transition from summer into winter. In the northern hemisphere, the start of autumn is generale of which are based on the months of the year while others are based on the equinox and solstice.
Winter is one of the four seasons of temperate zones. North American calendars go by astronomy and state that winter begins on the winter solstice and ends on the vernal equinox. Calculated meteorologically, it begins and ends earlier (typically at the start of the month with the equinox or solstice) and is the season with the shortest days and the lowest temperatures. Either way, it generally has cold weather and, especially in the higher latitudes or altitudes, snow and ice. The coldest average temperatures of the season are typically experienced in January in the Northern Hemisphere and in July in the Southern Hemisphere.