As you've no doubt noticed with a sense of glum resignation, the nights are drawing in and those sun-dappled summer mornings have given way to frost and mizzle.
And now it's official: autumn is official here, as today (September 22) marks the autumnal equinox.
But what actually is this mysterious equinox, the harbinger of the deep, dark depths of winter [and the good stuff like roaring fires and Christmas presents]?
Well it's actually one of two equinoxes we have every year. The other one is at the start of spring, and it heralds the warmer weather (well, the slightly warmer weather).
This means the southern hemisphere is going through its spring equinox now, and we in the northern hemisphere have the autumnal equinox.
An equinox takes place when the sun falls into line with the equator of the earth, meaning day and night share an equal amount of time. Neither the north nor the south poles is more tilted towards the sun.
From now on, the earth will continue tilting more towards the south pole - so our nights become longer and the daytime shorter.
Of course this also means the southern hemisphere receives more light at this time of year, which is why people on that half of the planet will be celebrating the spring equinox instead - and looking forward to their own endless summer nights.
The term equinox is latin for equal night and to reflect ancient traditions, some people travel to historical places like the Stonehenge to celebrate, according to Cambridge News. But if you're going to try it out this year, probably best to take a cardie with you - it's pretty brass out there.