I’ve been doing a lot of Southern European travel during the off season. Spain, Portugal, Italy. The weather is often mild and at worst, brisk. Good for walking and avoiding crowds.
This trip I learned that major Italian destinations fill up between Xmas and New Year like it was June. I arrived in Florence before Xmas, and it was as expected, but was literally swarmed the day after. I traveled to Naples, 12/27-1/3 and found it was even worse. Public transit was so full that buses would stop and no one could get on. Three hour waits for lunch at many restaurants in the old center. Mobs everywhere.