Spring

According to an astronomical definition, spring begins on March 21, the vernal equinox in the northern hemisphere and lasts until June 21, the northern summer solstice.

Summer

The seasons are popularly considered in some Western countries to start at the equinoxes and solstices, based on astronomical reckoning. Thus, in the Northern hemisphere, based on astronomy, summer begins on the day of the June solstice and ends on the September equinox. When it is summer in the northern hemisphere it is winter in the southern hemisphere, and vice versa.

Autumn

Autumn (also known as fall in North American English) is one of the four temperate seasons. Autumn marks the transition from summer usually in September (northern hemisphere) or March (southern hemisphere) when the arrival of night becomes noticeably earlier. In the northern hemisphere, the meteorological start of autumn is on 1 September and it ends on 30 November;[1] in the southern hemisphere it starts on 1 March and ends on 31 May. The astronomical start of autumn is on 22 September and ends on 20 December in the northern hemisphere, and 20 March and 21 June in the southern hemisphere. Autumn starts on or around 7 August and ends on about 6 November in solar term.

Winter

Winter is one of the four seasons of temperate zones. Calculated meteorologically, it begins on the solstice and ends on the equinox. It is the season with the shortest days and the lowest average temperatures. It has colder 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.