The astronomical spring lasts until the summer solstice, which this year lands on Monday, June 21.
Spring’s first day comes earlier with the meteorological definition, which is much simpler, splitting the year into four seasons of three full months based on the calendar, making it easier to compare seasonal and monthly statistics.
This means that every year spring begins on March 1 and lasts until May 31, with summer starting on June 1, autumn arriving on September 1 and winter following on December 1.
In theory, this means that everywhere on the planet should get 12 hours of daylight and darkness on those days, although this is complicated slightly by the Earth’s atmosphere affecting the way we see sunlight.
For six months each of the year, either the northern or southern hemisphere is pointing slightly more towards the sun, bringing the warmer temperatures of spring and summer.
The autumnal and spring equinoxes mark the point when the two hemispheres swap over, while the summer and winter solstices denote the sun reaching its most northerly and southerly points.