I understand that Chanuka is in the winter months because that’s when the world is darkest and Chanuka is about bringing light into the darkness. Are there other, more text-based reasons for Chanuka occurring when it does?
Surely, the fact that Chanuka, called the Festival of Lights (chag urim), occurs in the winter is not coincidental. The physical world mirrors the spiritual one, and the forces at work in the spiritual realm that resulted in the victory of the Maccabees over their oppressors were played out in the physical world as well, bringing the light of inspiration and redemption to the Jews in their darkest hour.
Still, the simple reason why we observe the days of Chanuka at this time is because that is when the miraculous events actually took place. Thus our Sages taught, “What is Chanuka? Beginning with the 25th of Kislev, eight days of Chanuka are observed…For when the Greeks entered the Sanctuary they defiled all the oils, and when the Hasmoneans prevailed and vanquished them they found only one jar of oil with the seal of the High Priest, enough to burn one day — but a miracle occurred and it burnt for eight days. A year later the Rabbis designated these days as a holiday for praise and thanksgiving” (Shabbat 21).
There are other sources that are understood as textual allusion to Chanuka as well.
The word Chanuka, meaning dedication, intimates a holiday on the 25th since “chanu” suggests rest or respite and the letters for “ka(h)” — kaf and hey — have a numerical equivalent of 25. Also, the 25th word in the Torah is “or” — light. Furthermore, the 25th place of encampment in the journeying of the Children of Israel in the wilderness was Hasmonah — a suggested reference to the Hasmoneans victory on the 25th.
The Midrash says that on the 25th of the month of Kislev the work of the Tabernacle was concluded but it was not inaugurated until the 1st of Nissan. Kislev therefore missed the inauguration that it was entitled to because of the Tabernacle having been completed therein. G-d therefore said, I will make restitution to Kislev in the time of the Hasmoneans when the Maccabees will reinstate the Sanctuary (Yalkut Melachim 184).
In fact, a precursor to the significance promised to this day as a day of inauguration occurred when the Jews returned from the Babylonian Exile. After having begun to rebuild the Temple, their work was interrupted for twenty-two years because of enemy intrigue and opposition. When their work of rebuilding was resumed, they erected the foundation of the Sanctuary on the 24th of Kislev. During the night of the 25th, they celebrated the inauguration.
Parshat Emor of the Torah lists all of the festivals of the year starting with Shabbat and concluding with Succot. The account of the festivals is followed by the commandment to maintain an Eternal Light in the Sanctuary. It has been suggested that the mentioning of the festivals concluding with Succot in proximity with the Eternal Light hints to a future day when a festival of kindling light would follow the Torah holiday of Succot.
There is a similar allusion to Chanuka in Parshat Beha’alotcha based on the fact that the passages describing the dedication of the altar are directly followed by a passage about the golden menorah. Ramban relates a Midrash that when the tribes each brought offerings for the dedication of the altar the tribe of Levi had not been included. G-d told Moses: “Speak to Aaron and tell him that one day there will be another inauguration involving the kindling of lights. Through your sons I will perform miracles and bring deliverance to Israel. This will be called by their name, the Chanuka of the Hasmoneans.”
Furthermore, the Midrash continues, G-d told Moses to relay to Aaron: “You are destined for something greater than the inauguration of the altar. The altar offerings are only brought while the Sanctuary stands. The lights of Chanuka, however, will burn forever. Even after the Temple will be destroyed, the light that will be kindled by your offspring the Hasmoneans will continue to shine through the long and bitter darkness of destruction and exile until they ignite the sparks of the final redemption.