Many halachic authorities dating back to the Rishonim have suggested that the difficult winter weather played a role in the menorah’s being moved indoors. The Ritva (Rabbeinu Yom Tov ben Avraham Alashbili), commenting on the Gemara’s statement “In the time of danger he should place it [the menorah] on his table and that is sufficient,” writes that “my master, my teacher, would say that when the wind makes it impossible to light outdoors, light indoors.” The Ritva broadened the Gemara’s instruction to light indoors due to danger to include difficult winds, rain and snow which prohibit one from lighting the menorah outdoors. Rav Yechiel Michel Epstein, the well-known early 20th-century halachic authority, takes a similar approach. He writes that although there is no physical danger, the weather is enough of a deterrent to prevent one from lighting outdoors.
The weather-factor approach raises two questions. One, if the weather does indeed deter one from lighting outdoors, how could the Gemara suggest doing so as the ideal way of lighting? Two, what was done during Talmudic times and during the generations when there was no danger? Rav Yaakov Emden, in his Responsa She’eilat Yaavetz, addresses these questions. He suggests that during the generations when the menorah was lit outdoors, a glass enclosed case was made to house the menorah. This contraption was made in order to fulfill the requirement to light outdoors while keeping in line with the halachah that the lights of the menorah have to be seen. Rav Emden responds to one who questioned the propriety of using such a case and writes that one could, and should, fashion such an enclosure in order to light outdoors. Rav Emden concludes that because of the expense of building the glass enclosure, and because of the fact that he never saw earlier rabbinic figures light outdoors in such a fashion, it is unnecessary to go to such lengths unless it is easy to do so. Although the She’eilat Yaavetz does suggest that one can light outside if the appropriate fixture is established, the Aruch HaShulchan states unequivocally that one should not create such a structure in order to light outdoors.
Moshe Walter, “The Movement of the Chanukah Menorah Indoors: An Historical and Halachic Analysis“, Hakirah 16 (Winter 2013), 237-238.