Equinox, when the length of the night and the day are nearly equal is marked by Google by an animation of falling leaves in the northern hemisphere.
Marking the end of summer and the onslaught of autumn, there are two versions of the doodle animation — one for the southern hemisphere for the first day of spring and one for the northern hemisphere for the first day of Autumn.
"Today's doodle celebrates the new season with the orange glow of fall's falling leaves," Google said. "It's also the beginning of the cooler temps that will be with us until spring comes around," it added.
Spring in the southern hemisphere and autumn equinoxes and the summer (longest day) and winter (longest night) solstices mark the start of the astronomical seasons each year.
In 2016, the astronomical autumn will start on 22 September and end on 21 December with the winter solstice.
The arrival of Autumn aside, temperatures are set to rise in the UK as hot air from Europe is set to sweep in, the Mirror says.
Temperatures of 21C are expected on Thursday 22 September, with the mercury expected to rise even further over the weekend. Highs of 25C are expected, which is about 10C above average for this time of the year.