Rabbi Arthur O. Waskow: Hanukkah and the Winter Solstice
It is possible that the Syrian Greeks chose the latter part of Kislev, the 25th of Kislev, in fact, to desecrate the Temple by making their own sacrifices because it was the time of the winter solstice and the waning of the moon. It is equally probable that the Maccabees used the 25th of Kislev for the anniversary of the rededication by recapturing a pagan solstice festival that was popular among the Hellenized Jews of the time.
This is a fascinating thesis; please follow the link below to read the full article:
https://www.myjewishlearning.com/article/hanukkah-and-the-winter-solstice/