Hello friend and thank you.
There are both historic and modern heathen celebrations during the close of summer and through autumn times.
Personally, I only celebrate ‘Winternights’ (also known as Vinternatt, Vinternettene, Vinterdag and Høstblot) as a matter of course.
In Norway, they have a set date for the annual ‘Winternights’ which is held 28 days after Autumnal equinox (14th October for the Northern Hemisphere).
It is regarded as the first day of Winter and in past times, when the Scandinavian people marked the date on a primstav, it would signal the time to swap sides on the primstav from the summer side to the winter side. Winternights was always marked with the image of a mitten.
It doesn’t necessarily have to have a set date in modern Heathenry and can vary dependant on location (ie. it will be celebrated later in a country with a longer warm season) and personal preference. Many people celebrate based only on when they feel the shift to very cold weather occur. So they read the land and wait for the sudden temperature drop that usually occurs in late September or early October (for Northern Europe) and use that as a sign that it is time to honour the powers.
The Winternights blot is usually specifically dedicated to the Diser (Dísir), Alver (Elves) and Ancestors.