While riding the train from the Musée d'Orsay to the Eiffel Tower we noticed a young American couple, probably early 20's, riding in the same car. They were going to the Eiffel also; unfortunately, they were wearing only light clothing like you might wear around Southern California at this time of year and it's certainly not like California here in late November.. We came up from the Metro station to pouring rain and wind and probably 40°F at best. They didn't seem too concerned, but I doubt they ever made it into and up the Tower. We had parkas, umbrellas and hats and were still cold. Only one of the lifts was open and we had to queue up for at least half an hour in the rain and wind to get in. Many of the people in line, all tourists of course, were unprepared with no umbrellas and were like drowned rats by the time they got into the lifts. It was worth it though; the city was beautiful in the wet twilight and it actually stopped raining by the time we got to the top area, which is out in the open. Still cold though.
The mid level is partially covered so you can spend time looking out from there even if it is raining.
I'm sure the lighting on the tower is extra special for the holiday season.