Milan (where I spend about a month a year in hotels) can vary considerably because of the fairs/trade shows. During peak weeks prices double (or more) and then bounce back to normal as soon as the event is over (my travel is pretty flexible, so I work my way between the fairs). A very silly example is the Excelsior Gallia. The price for one night Weds Sept 7 is 20,000 Euros! Sept 28 a bit over 1000. For October 1 540 Euros. But I reserved a while ago and prices seem higher than when I reserved.