When you're packing your suitcase, you'll need to plan for many different types of weather. It doesn't hurt to check the forecast for the cities you'll visit before you go, though, on average, highs in October are around 70 degrees Fahrenheit, and lows are in the 50s, with a chance of rain. If you're traveling to the Alps, though, pack as if a snow storm could hit anytime and bring a warm coat, boots, gloves and hat. In other parts of the country, you could find that your entire trip is hot and sunny, or the opposite. As a general precaution, bring a lightweight raincoat. If you're short on space, don't bother packing an umbrella -- if it gets that bad you can pick one up while you're there. The umbrellas in the tourist shops and drug stores might be of poor quality, but they'll be cheap, so you won't have to feel bad about leaving it behind.
With those fluctuating temperatures, packing lightweight layers is going to be your best bet. That might mean a T-shirt or a button-down shirt for daytime, to which you can add a cardigan or a lightweight jacket when the temperature drops. Tank tops may be appropriate on the street during warm days, but since they're not acceptable for visiting churches or other religious sites -- which abound in Italy -- wear short-sleeved shirts in lieu of sleeveless tops. Also bring along a scarf that can dress up an outfit as well as help you warm up. A hat is never a bad idea, either, since it will also protect you from getting too much sun.
People in Italian cities tend to dress a little more formally than people in the United States, meaning they tend to choose slacks over jeans, and skirts or lightweight pants over shorts. They also tend to favor darker colors over bright colors -- though that can change quickly according to the whims of the fashion industry. Don't go changing your entire wardrobe just to fit in, but if you're concerned about not sticking out like a sore thumb, it doesn't hurt to think a little more fashion-forward. For evenings, pack a dark-colored, well-fitting upscale outfit or two that you reserve just for evening time. Bringing along a lot of flashy jewelry or accessories is a way to peg yourself as a mark for pickpockets, so leave that stuff at home.
If you're in the market for new goods, leave some room in your suitcase for a new pair of shoes. Italians love shoes, so don't be surprised if you come home with a new leather pair. In any case, bring along a versatile pair of walking shoes that can double as nighttime footwear. Skip the white tennis shoes -- they'll make you stand out as a tourist right away. It's unlikely to be warm enough for open-toed shoes, but a pair of flip-flops is always a good thing to have when you're headed to the beach or a public pool.
