Clothes to pack?

For shoes - whatever ones you have that are sturdy, and you can walk in for hours and hours are best, sandals or closed toes. I have been to Europe several times in summer and always wear sandals. Before any trip I always monitor the weather forecast for my destination cities on the weather channel website, and pack accordingly. It doesn't make sense to guess about the weather when you can get reasonable info on what it is likely to be. You will not be able to go into churches wearing a sleeveless shirt or short skirt, so bring something that is acceptable when you plan to visit them. In the cities skirts, sundresses, capris are fine. You are going to some coastal towns, so bringing a bathing suit seems like a good idea, particularly if it looks like it will be hot.
Nights may be cool, so always bring a jacket or sweater.

Sounds like you are planning well. Some suggestions: If you can find it a fold-up breathable rain jacket is a good idea (any outdoor shop should sell them; Short-sleeved tops are more appropriate than tanks or sleeveless when visiting churches. You want breathable tops - if its hot and humid most man-made made materials will be very uncomfortable. Rather than a sweater or a jacket, consider a pashmina or shawl, useful as a cover up for visiting churches, as an evening cover-up and as a blanket on the plane. Yes to a bathing suit and use a long T-shirt as a cover-up/sleep shirt. I would also consider taking a dress, perhaps a sun-dress which you can dress-up for evening? Eccos and similar are great. Just be sure you have good shoes if you are planning in hiking the trails in the Cinque Terre. A pair of slightly more dressy sandals are good for the evening - I bought a pair of fuschia coloured Merrells which match the dress I plan wearing most evenings. Of course bear in mind that if you find yourself short on anything you can buy it in Italy - for example, pashminas are usually cheaper there than in North America and local markets often have great buys. Enjoy Italy!

I always take a lightweight sweater with me. It's great for the plane ride over, and I find myself wearing it at night and in churches. I don't personally wear sleeveless shirts, so they don't go with me. If you really think you will sit on a beach in the CT, take swimsuit. I've packed mine several times, and it never comes out of the suitcase. the pools at hotels are NOT heated, and are very cold. I usually pack a scarf as well to dress myself up and to use to cover shoulders when needed. I have a pair of Chaco sandals that go with me on every trip. They are 10 years old now, but they are my go- to shoes. I tend to wear them all day/night. That being said, I also take one pair of closed toe shoes too. Always bring 2 pairs of shoes, you will want to switch them out. No matter how comfortable your shoes are....your feet will thank you for the change. A rain jacket with a hood is a good idea. You just never know what you might encounter for weather, better to be safe than sorry. One item I've started to bring is a black linen skirt. It's great to get "dressed up" for eating out at dinner time. I get tired of my capri pants.

Thanks for the great responses - very helpful! I'm trying to pack as light as possible, so double (or triple) duty clothes are a must (& definitely an extra pair of shoes!).

It will be hot. I am taking sleeveless shirts. Rick Steves suggests taking a scarf as a cover up for cathedrals. I use a cotton shawl because it doubles as a belt. If I need to cover my shoulders I take it off my waist and put it over my shoulders. In the rain it goes over my head.

A cotton shawl tied around your waist will be hotter than a lightweight cotton shirt with 3/4 sleeves. My best travel shirt is a lightweight cotton gauze that is cool, breezy, and washes and dries fast. it keeps the direct sun off my arms and covers my shoulders for church visits. Capris and lightweight knee-length skirts are good. You'll want tops in various sleeve lengths, from sleeveless to 3/4 sleeve. Don't forget a rain jacket or umbrella (you can buy one there from the umbrella sellers that pop up as soon as the rain starts).