When does autumn start?
12/09/23 Filed in: Seasons
When does autumn start?
For meteorologists the UK autumn starts on 1 September. This was based on the warmest months defining summer: June, July and August; and the coldest months defining winter: December, January and February. Spring and autumn filled the gaps.
Astronomical seasons are based on the position of the earth, more specifically the earth’s axis through the north pole, in relation to the sun and are defined by two solstices and two equinoxes. At the winter solstice, around 21st December, the North Pole is tilted away from the sun; at the summer solstice, around 21st June, the north pole is tilted towards the sun. The equinoxes occur midway between the two extremes.
By Tauʻolunga - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=927625
Seasons never changed suddenly from one day to another – it was a gradual shift. Autumn crept in as daylight hours shortened, temperatures dropped and leaves changed colour. The shift went both ways: I am writing this after a cool wet summer followed by a late summer heatwave. We had a bit of autumn, now it is summer again but there will be a lot more autumn soon. Cyclamen and colchicum, traditionally autumn blooming, are flowering but in summer heat. As climate change disrupts the weather it becomes even more pointless to assign the change of season to a single day or even expect a gradual progression from one season to the next.
Astronomical seasons are based on the position of the earth, more specifically the earth’s axis through the north pole, in relation to the sun and are defined by two solstices and two equinoxes. At the winter solstice, around 21st December, the North Pole is tilted away from the sun; at the summer solstice, around 21st June, the north pole is tilted towards the sun. The equinoxes occur midway between the two extremes.
By Tauʻolunga - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=927625
Seasons never changed suddenly from one day to another – it was a gradual shift. Autumn crept in as daylight hours shortened, temperatures dropped and leaves changed colour. The shift went both ways: I am writing this after a cool wet summer followed by a late summer heatwave. We had a bit of autumn, now it is summer again but there will be a lot more autumn soon. Cyclamen and colchicum, traditionally autumn blooming, are flowering but in summer heat. As climate change disrupts the weather it becomes even more pointless to assign the change of season to a single day or even expect a gradual progression from one season to the next.
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