We are planning our first europe trip during winter break- late December to about Jan9. Will any of the major attractions (Pompeii, Vatican, Eiffel Tower, major Museums, etc) be closed during that time frame?
Yes, some of them certainly will be but you'll need to go to the website for whichever ones you may visit to see what the closing dates are. This is always a problem for people who travel over Christmas and New Years. Public transportation will also be curtailed.
Why don't you reschedule your trip for spring? The charm of Paris and Italy are sitting at the sidewalk cafes, people watching etc.... Christmas is a big holiday in a catholic country like Italy!! You will really need to plan and research what will be open (restaurant wise) on Christmas eve and Christmas Day.
We were in Paris this last Dec/Jan from the 29th - 9th. We didn't a problem with places being closed (except we couldn't go past the first level of the Eiffel Tower due to freezing temps) and transportation (the metro) didn't seem to be any different than usual. I will say that what I missed the most was being able to enjoy the outdoor cafes and just hanging out people watching. It was too darn cold for that! Although we had a great time and it was beautiful, I'll stick to warmer weather next time. Also, I highly recommend renting an apartment.
In general, what I've noticed over the years here on the Helpline is that Americans have a tendency to under-estimate the winter temps in northern Europe. (Canadians don't do this, their latitudes are more comparable to those of much of northern Europe). This tendency to under-estimate the winter temps in the European interior can actually be seen in a couple of current topic threads.
Looking on a map, much of Europe is well north of the latitudes of much of the US. The European interior can be expected to be colder than what many Americans are used to--although the moderating influence of the English Channel and Atlantic have the good effect of keeping parts of Europe near large bodies of water somewhat less cold than the European interior.
Kent is right about the temperatures, especially for those of us that live in relatively warmer climates. Even though I thought I was thoroughly prepared, I was often too cold for comfort. I've only been in Austin during the late Spring, but I doubt it gets nearly as cold as most of Europe.