As noted above, the winternights (veturnætur) seemed to have been officially celebrated over a course of three days, on the first full moon following the autumn equinox, which was the full moon of the month which Bede calls Winterfilleth (“Winter Full”). They are probably the best preserved of the heathen holidays, and this may be because of their role as the start of the natural year. Generally, the winternights fell at a time when the harvest was finished, the days were darkening, and the cold was beginning to settle in. Bede refers to the month following Winterfilleth as Blodmonath (“Blót-Month”) and says that this was the time that the Angles slaughtered their cattle and “consecrated (the slaughtered cattle) to their gods”. This was traditionally the time of year when the herds were culled so as to ensure enough feed to survive the winter. The winternights, the literal beginning of the seasonal year, marked the start of this season. Celebrations seemed to revolve around the local farmstead, and were essentially “invite only”. In Gísla saga Súrssonar we are told “It was the custom (siðr) of many in that time to celebrate winter and have feasts (veislur) and winternights sacrifice (Veturnáttablót).” Flateyjarbók says “the feast (veisla) was prepared for the winternights. Few of those invited came because the weather was very stormy and troublesome.” Eyrbyggja saga says:
The next autumn at the winternights, Snorri the Goði held an autumn feast and invited all of his friends. There was heavy ale drinking there.
As mentioned above, sacrifices at this time would have been normal. Who the blót would have been directed to may have varied. But two particular recipients are given support in the sources. Freyr and the female spirits collectively called Dísir. Frey’s connection to winternights is explicitely stated once, and inferred through various other sources. In Gisla saga Súrssonar it says “that autumn, Þorgrímur planned a feast for winternights to welcome winter and make a sacrifice to Freyr.” In Óláfs saga helga, the Christian poet Sighvatur Þorðarson is said to have been denied admittance to a farm in the autumn because the locals were participating in a “sacrifice to álfar” (álfablót). We may note that the álfar are a part of, perhaps synonymous with the Vanirand in any case, were strongly associated with Freyr. Further evidence for Frey’s connection to the winternights can be found in the traditional harvest celebrations involving horse races and fighting in Iceland around the public autumn Þing, found throughout sagas, and which the later bishop Oddur Einarsson prohibits priests from attending in 1592. One might remember that the horse was an animal sacred to Freyr. It is also interesting to note that the Völsa þáttr from Flateyjarbók describes the autumn rituals of a remote farmstead in Norway in which a horse phallus is preserved and treated as an object of worship. The phallus and the horse both being connections to Freyr may lend further evidence for associations between Freyr and the winternights, or at least autumn. In addition, Terry Gunnell notes that the autumn festivals commonly feature weddings in the saga accounts and suggests this may be evidence of a connection to Freyr. Weddings at this time may have been for the sake of practicality, or may have been related to the start of the new year. Irregardless, as the deity associated with marriage it is not unrealistic to imagine Freyr having a role in these rituals. It should be noted that both the álfarblót and Völsa Þáttr take place in autumn but there is no written reference to winternights, so their connection to it conjecture. On the other hand, the Dísir, who most certainly were worshiped at winternights, have a wealth of preserved references which we may analyse.
In short, the Dísir appear to have been powerful female spirits that watched and protected family lines and individuals. Arguably they are connected with the continental Germanic matronae, and were associated with fertility and childbirth, as well as death and sometimes warfare. The Dísir were obviously more than deceased female spirits, and more akin to minor, local, or family goddesses. We find places named after them (Diseberg/Disevi (SV); Disen (Nor)) and they could have control over the life and death of individuals, and protect families and clans. They may have had associations with Freyja, whom Snorri calls Vanadís (Dís of the Vanir), and with Skaði, who is once referred to as Öndurdis (Ski Dís). Concerning the Dísablót, Víga-Glúms saga says “There was a feast prepared for winternights and a Dísablót and all should attend.” Egils saga also describes a Dísablot taking place in late autumn. Þiðranda þáttr in Flateyjarbók describes a Christianized description of a winternights celebration taking place in Iceland in which two groups of women described as Dísir appear, representing the older familial Dísir of a guest named Þiðrandi, and the new Dísir of Christianity. Þiðrandi’s old Dísir kill him to compensate for the lack of tribute they would recieve from the new religion, though it is interesting to note that Þiðrandi’s companions had procured an ox which they named Spámaðr (prophecy-man), to be sacrificed. A second point of interest, which we shall see become a common feature of the winter half of the year, is that during the feast, the guests were told not to go outside, “because great harm will come about.” The Dísir in this instance are portrayed as dangerous entities from outside the farmstead which have moved in and subsequently kill Þiðrandi. While the connection between the Dísir and the wilderness is probably Christian, the motif of dangers from the “outside” moving into the “inner yard” is common, beginning in winternights and lasting through the winter period. The role that the Dísir played may have been two-fold, and demonstrate their role as protective spirits connected with fertility, birth, and as well as spirits who were associated with death. In addition to Frey’s connection to weddings, it makes sense that family goddesses would be gifted, in the hope for fertility, and perhaps childbirth later that year. That they would have played a role with the weddings that took place at the beginning of the natural year is not surprising, but we will see another activity that frequently took place during the period following winternights with which they may also have been associated.
Frequently during the culling of the flocks, farmsteads would give sacrifices and hold rituals in an attempt to foresee what the year had in store for them. With the harvest completed, surviving the winter was a matter that in many ways was “up to fate” (the norns?). Prophecy was a deep rooted part of heathen society, and this was a natural time to conduct such rituals. In Landnámabók it says “that winter Ingolfr held a great sacrifice to discover what the future had in store for him. The oracle told Ingolfr to go to Iceland.” “That winter” in this context almost certainly refers to the beginning of the winter and the time around winternights. In the account of Þiðrandi, a man named Þorhallr, who was called a spámaðr (man who gives prophesies) had been invited to the private winternights feast. Interestingly, this is the exact name that the bull they intended to sacrifice had been given. Eiríks saga Rauða provides a detailed account of a travelling seiðkona (seiðr woman) who spends the winter period visiting households and foretelling how their year will fare. In the account she spends what we may deduce is the period around winternights at a farmstead in Greenland, where she is treated with a feast and in return, performs a ritual enabling her to tell those present how they will fare that winter. In Örvar-Odds saga, a seiðkona and völva named Heiðr travels to different feasts and tells people about the coming winter and their fate. Seiðr was highly ritualized and generaly belonged to the sphere of the woman. It has been demonstrated convincingly by Neil Price and others that a central part of the seiðr complex involved communicating with spirits, including the dead, fylgur, and Dísir. We may conclude that there was a custom of fortelling the fate of the winter and new year around the time of winternights and that at that same time there were sacrifices held to the Dísir. We may also postulate that these two customs were connected. Perhaps prophecies were held and the Dísir sacrificed to in hopes for their protection; or perhaps sacrifices were held to the Dísir as part of a prophetic ritual, and in turn they helped provide information about the coming winter, in the same (or accompanying) role as the seiðkonur described above.
The quarter of the year which began on the full moon of winternights marked a period of expanding darkness. Vafþrúðnismál suggests that night was made for the gods and day was fashioned for men.  Winter was the “night” for the year, and on the basis of the above it was a liminal period associated with magic and death. The festivals and rituals held at this time seem to have been concerned with both procuring and foreseeing a good year. The old heathen formula, “til árs ok friðar” (to prosperity and peace for the year), preserved even in a Christian context in Gulaþings-lov is especially relivent to Freyr, who was likely associated with the harvest, which occures in the month prior to winternights, as well as to the rulership, charged with keeping the peace of the realm. The horse races and fights held at official autumn Þing events in Iceland and Norway may be the remnants of his worship, and as noted he is mentioned as one of the recipients of winternights sacrifices in the sagas. At the same time, we see invite-only feasts and sacrifices at which the goddesses of the family were worshipped, and prophecies delivered relating to the fate of the coming winter and year. We might speculate that the poem Völuspá (prophecy of the völva) which was originally either a ritual or drama performance, may have its roots in the winternight prophecies for the coming year, or stem from that tradition. We might also speculate that Frey’s connections to winternights may have at some point been connected with the more public Þing festivals at that time, while the Dísir remained the recipients of family rituals.
 – Bede: The Reckoning of Time, 1999, p. 53.
 – Gísla saga Súrssonar, 1943, p. 17. My translation.
 – Flateyjarbók I, 1860-1868, p. 466. My translation.
 – Eyrbyggja saga, p. 98.
 – Gísla saga Súrssonar, 1943, p. 27.
 – Óláfs saga helga, in Heimskringla, 1944. p. 314-315.
 – Hall 2007, p. 27.
 – Grímnismál, st. 5, in, Eddadigte, 1962.
 – Solheim, 1956, pp 51-78.
 – Gunnell, 1995, p. 35.
 – Hrafnkels saga Freysgoða, 1965, pp. 14-15.
 – Flateyjarbók II, 1860-1868, pp 441-446.
 – Gunnell, 2006, p. 65.
 – Brunet-Jailly, 1998, p. 216; “If marriages are to be celebrated (libations are poured to) Freyr.” My translation.
 – Simek, 1993 p. 61; Davidson, 1998, p. 47; Turville-Petre, 1964, pp. 221-227.
 – Simek, 2007, p. 205.
 – Gunnell, live lecture 17, 2013, and Simek, 2007. Hundreds of stone altars engraved to the matronae have also been found throughout continental Europe.
 – Gunnell, 2006, p. 130.
 – Snorra-Edda, 2003, p. 125.
 – Snorra-Edda, 2003, p. 38.
 – Víga-Glúms saga, 2001, p. 17.
 – Egils saga, 2008, p. 84.
 – Flateyjarbok I, 1944, pp. 465-476.
 – Flateyjarbók I, 1944, p. 466.
 – Sigdrifumal, st. 9 mentions their role in child birth.
 – Sundqvist, 2002, p. 214.
 – Landnámabók Íslands, 1948, p. 8.
 – Saga of Olaf Tryggvason, Flateyjarbók.
 – Price 2002 provides a comprehensive overview of Seiðr. In short for our purposes, it is a form of sorcery, which entails in part, the fortelling of the future by communicating with spirits.
 – Íslendinga saga, 1985, pp. 523-524.
 – Fornaldarsögur Norðurlanda, 1959, p. 205.
 – Price, 2002 primarily; see also Dubois, 1999, pp. 52 and 122-138.
 – Vafþrúðnismál, st. 11 and 13.
 – Gunnell, 2006.
 – Den Ældre Gulaþings-lov, 1846, p. 7.
 – See Dronke, 1997, Gunnell, 1995.