Seasons: Meteorology and astronomy. When do spring, summer, autumn, and winter start and end? It depends on which definition you are using and whether you are north or south of the equator.
Four Seasons
The Earth’s axis is tilted slightly relative to its orbit around the Sun. This is why we have seasons.
How exactly do the seasons work? In most cultures, including all Western countries, the year is usually divided into four seasons:
- Spring
- Summer
- Fall
- Winter
Since there are 12 months in a year, each season lasts about three months. However, the start and end dates of the seasons vary depending on who you ask. Two methods are most commonly used to determine the dates of the seasons: astronomical and meteorological definitions.
Astronomical Terms and Definitions
Earth: Living Planet
Astronomical season
The astronomical definition uses the dates of the equinoxes and solstices to mark the beginning and end of the seasons:
- Spring begins with the vernal equinox;
- Summer begins on the summer solstice;
- Autumn (autumn) begins at the autumn equinox; And
- Winter begins on the winter solstice.
What are equinoxes and solstices?
The beginning of each season marks the end of the previous season. Since the time of the equinox and the solstice varies from year to year, the lengths of the sidereal seasons within a year and between years also vary.
Days of equinoxes and solstices around the world
Weather of the seasons
According to the meteorological definition, seasons begin on the first day of the month including the equinoxes and solstices. For example, in the northern hemisphere,
- Spring lasts from March 1 to May 31;
- Summer lasts from June 1 to August 31;
- Autumn (autumn) lasts from September 1 to November 30; And
- Winter lasts from December 1 to February 28 (February 29 in a leap year).
Face To Face – Season Opposite
The seasons in the Southern Hemisphere are opposite to those in the Northern Hemisphere. For example, by the definition of sidereal seasons, the June summer solstice marks the beginning of summer in the northern hemisphere, but the beginning of winter in the southern hemisphere. The same rule applies to other seasons.
The weather seasons in the Southern Hemisphere are also opposite to those in the Northern Hemisphere:
- Spring starts on September 1 and ends on November 30;
- Summer begins on December 1 and ends on February 28 (leap year is February 29);
- Autumn (autumn) begins on March 1 and ends on May 31; And
- Winter starts on June 1 and ends on August 31;
Sun: Our star at home
Different countries, different seasons
The question of using which definition has divided the countries and regions of the world. For example, Australia and New Zealand use the weather definition so that spring begins on September 1 every year. In many other countries, both definitions are used, depending on the context. In Ireland, Saint Brigid’s Day on February 1 is generally considered to mark the beginning of spring in the ancient Celtic calendar system. Some cultures, especially in South Asia, have a calendar that divides the year into six seasons, instead of the four with which most of us are familiar.
In Finland and Sweden, the dates of the seasons are based not at all on the calendar, but on the temperature. This means that the seasons in each county begin and end on different days, depending on their region and climate.
In Iceland, the first day of summer, a public holiday, falls on the first Thursday after April 18 슬롯게임 사이트.