WINTER 2018 is fast-approaching, but when does the coldest season of the year officially start? And why are there two dates?
 |
| Winter 2018: When does winter officially start? Why are there two different dates? |
The clock has gone back, the evenings are drawing in, and it is starting to get cold.
Autumn is well underway, meaning Christmas is fast-approaching.
With the UK experiencing intense heatwaves over the summer, some forecasters believe we could be in for the coldest winter for eight years.
Air moving from the north pole could see temperatures plummet to -11C.
Winter may be on its way, but there are two approaches to determining exactly when it starts.
When winter officially starts depends whether you are referring to the astronomical or meteorological dates.
The astronomical seasons depend on the position of the Earth’s orbit around the sun, taking into account equinoxes and solstices.
Meteorological seasons take into account the annual temperature cycles and the gregorian calendar.
This means, according to the meteorological winter, the last season of the year begins on December 1, 2018 and ends on December 28, 2019.
The meteorological calendar divides the seasons into four equal seasons.
 |
| Winter 2018 There are two different dates |
They are spring (March, April, May), summer (June, July, August), autumn (September, October, November) and winter (December, January, February).
For those adhering to the meteorological calendar winter starts on December 1 each year.
According to the astronomical calendar, winter starts on December 21, 2018 and lasts until March 20, 2019.
This date can change each year, because it depends on when the winter solstice falls, and the spring or vernal equinox starts.
The winter solstice is the shortest day of the year, while the spring equinox is when the day and night are almost equally long.
 |
| Winter 2018 It’s going to be a cold winter |
The dates can vary between December 20 to 23, and March 20 to 21 every year in the Northern hemisphere.
The day after the Spring equinox is counted as the first day of spring.