A little information and some opinions for next time.
It is possible for any hen of any breed to go broody at any time of the year. Some breeds and crosses like Leghorns, Rhode Island Reds, and the commercial egg laying hybrids have mostly had the broodiness bred out of them so they very seldom go broody, but every now and then you'll see a story on here where one does. It is highly unlikely your Leghorn will ever go broody but not totally impossible.
That was information, now for opinion. Chickens used to be bound to the natural cycle of seasons but we domesticated them. We bred certain traits into them. They never have a slow season where food is scarce. They often get artificial light, either intentionally or by accident like street lights or security lights. Some even get heat during winter. The seasons don't mean what they used to for the chickens. It is still fairly unusual for a hen to go broody in winter but it can happen. You get some stories on here about that.
While it is possible a Leghorn could go broody in November in the northern hemisphere it would be really unusual.
I've had hens that have a lot of the broody traits, staying on the nest, defending the nest, walking around fluffed up and making that pucking sound, and whatever else a broody hen is supposed to do and still not really be a committed broody deserving eggs to hatch. My test before I give eggs to a broody hen is that she has to spend two consecutive nights on the nest instead if in her normal sleeping spot. Not one night, it has to be two consecutive nights. That test may fail me one day but so far it hasn't. That other stuff is an indication she might be broody or might be thinking about going broody, to me it is not a definite test.
