Key Points
- 1 September marks the beginning of spring in Australia.
- But how are the seasons measured elsewhere?
Spring has sprung, at least in Australia where the calendar ticking over to September means a change in the season.
Not everywhere follows the same schedule though.
While in some countries — such as Australia and New Zealand — seasons follow a calendar system and change every three months, in others seasons are based on astronomical timing.
Other places follow cultural customs or thermal indicators.
People often gather at Stonehenge during summer and winter solstice. Source: Getty
When do the seasons change?
Simply, it depends on who you ask.
In places like Australia and New Zealand, which follow the meteorological system, the seasons roll over on the same dates each year. Summer begins on 1 December, autumn on 1 March, winter on 1 June, and spring on 1 September.
Many other countries, including the United States and Europe, follow astronomical timing, which determines the beginning of a new season based on solstices and equinoxes.
Ask them and the new season will begin on September 23 at 11.03am - at least as far as the southern hemisphere goes.
Macquarie University astrophysicist Angel Lopez-Sanchez says astronomers define the change in seasons by a solstice (when the sun appears at its farthest distance of the equator) or equinox (when the sun crosses the equator).
"I was shocked, when I moved to Australia ... to see that everyone used the beginning of December, March, June and September as the change of season," he said.
"Seasons are defined by astronomy in a very accurate and precise way, down to the minute."
Meteorological and astronomical are not the only ways seasons can be determined though.
For thousands of years, Australia's First Nations peoples have measured seasons guided by the land and based on ecological factors, with the number of seasons changing in different areas.
Some countries — such as Malaysia, Indonesia, and others close to the equator — follow two seasons (wet and dry). Northern parts of Queensland, Western Australia and the Northern Territory also follow the wet-dry seasonal calendar.
Meanwhile, six seasons are recognised in some south Asian countries,
And in some European countries, such as Sweden and Finland, thermal seasons are determined based on mean daily temperatures.
With AAP
