Yes today is the autumn equinox, and as Carol Kirkwood pointed out on the Breakfast TV weather the start of the 'astronomical' autumn, which to me is much more preferable to the 'meteorological' autumn. They are both 'astronomical' in reality, it's just that in the days before computers it was much easier for climaticians (?) to calculate the mean value for a particular season by adding up just three numbers rather than 90 which entailed a bit more work - well that's my theory. The astronomical season isn't without its problems though, because as you know equinoxes don't always happen on the same day each year, so this year for instance the Autumn equinox starts on the 23rd of September and next year it's the 22nd, and that's why when I generate any seasonal stats that I use a fixed 21st of December, March, June and September as the start of Winter, Spring, Summer and Autumn. In these days of fast computers there is no reason why I shouldn't use the exact date of the equinox to compute seasonal means from my various climate stats though, but although I am a purist when it comes to climate stats I am not that daft!

See blog for a graph of daily CET values, anomalies and spells and a chart grid of UK MSLP analysis for Summer 2015 (21 June - 20 September)

https://xmetman.wordpress.com/2015/0...day-of-autumn/