Clothing in Italy

How much does this expectation extend to other public places?

Zero, the God who thinks shoulder&knees to be disrespectful lives in the little box behind the altar. The same God when is everywhere but not in Churches couldn't care less about our knees&shoulders. The Guy is not exactly consistent, but you know... he/she/it is growing old.

Just be aware that the Sistine Chapel is actually a Church and you should dress accordingly if you want to enter the Vatican Museums. In Italian Museums you can (un)dress the way you like.

If you're outside and sightseeing, a tank top and shorts are not a problem. When inside a restaurant, especially a semi-formal or formal one (or at dinner time), I would ditch the tank top and shorts (definitely the tank top). If you have any loose linen clothes, they do really well in the heat. I would treat this like you're an ambassador of the US of sorts, and you'll basically be treated better when you're more put together when eating out. You can also "test it out" and just look around to see what others are wearing - if you don't fit in, it will be obvious and you'll feel it (the reverse could be true, too of course).

For example, if we're visiting the Colosseum, or a typical restaurant,
will there be any issues with wearing a tank top and shorts?

No, there will be no issue at all at archeological sites and most museums (see Dario's comment about the Vatican Museums/Sistine) although I personally wouldn't wear shorts and a tank to dinner but that's just me. It's in the churches that you're expected to cover shoulders and knees, midriffs, and not expose an immodest amount of décolletage. A short-sleeved shirt really isn't any warmer than a sleeveless one, IMHO, and Capri-length pants aren't really any warmer than shorts.

Take a look at some of these live cams and observe what people are wearing:
https://www.skylinewebcams.com/en/webcam/italia/lazio/roma/pantheon.html
https://www.skylinewebcams.com/en/webcam/italia/lazio/roma/piazza-di-spagna.html
https://www.skylinewebcams.com/en/webcam/italia/veneto/venezia/rialto-canal-grande.html
https://www.skylinewebcams.com/en/webcam/italia/toscana/siena/piazza-del-campo.html

I live in Texas and the temp has been above 100 for weeks now. I feel hotter when the sun is beating down on my skin, so I find loose linen dresses, skirts, tops etc. to feel much cooler. And don't forget a cute hat to keep the sun off your face and neck. It makes such a difference. They sell them everywhere if you don't want to pack one. If you are going to be out at historic sites, one of those sun umbrellas is a must. My husband scoffed when I took one to Pompeii, but he changed his tune once he felt how much cooler it was underneath it's shade! If you do choose a breezy dress, forget those bike shorts for underneath. Get a stick of skin protectant, like Gold Bond Friction Defense. It looks like a stick of deodorant, but you swipe it where your skin might rub together. It really works to stop "chub rub" if that might be a problem. Have fun in Rome!

You other repliers are right. But... When I was in Rome in July 2017, one day it was supposed to be 87 degrees. The high temperatures were probably 80-100 on the other days I was in Italy. I wore casual lace-up semi-athletic walking shoes (I just took the one pair), long (Patagonia if this matters) hiking pants, button-down shirts that I thought would be light weight enough (I had thought about buying a fishing shirt just before my trip but the ones I tried on that were labeled a size that should have fit me were still too baggy, but I suppose fishing shirts are supposed to be over-baggy so the breeze blows through the shirt), and a nylon boney sun hat (made by Colombia if this matters). I probably took the hat off inside the Vatican and inside churches. I was afraid people would think I was over-dressing. But I wanted to protect myself from the sun. I am a man if this matters.

Your timing is good, because the intense heat wave is expected to break on Thursday, and it should only be in the low 90's after that.

I was in Italy for several weeks in June. I saw all types of clothing. You wouldn’t look different wearing a nice tank top & shorts outdoors. The Italian clothing is more fitted in general. Depending on the age of your relatives & definitely for the Salerno passeggiata, you will want something nicer - maybe a pretty sundress.

(It was in the 90’s several days I was there, and I wore my dress several times because it was the most comfortable.)

To clarify on the tank top thing - everywhere but churches and church-run things (Vatican Museum etc), sleeveless tops and shorts are fine. The comments about tank tops in nicer dinner restaurants maybe are more about casual athleisure-type tank tops. Sleeveless blouses and dresses are perfectly acceptable, just the obvious caveat that in dressier restaurants at dinner you wouldn't want to wear the same very casual shorts and tank you wear all day. Walking around, want dinner, and stop in a casual cafe? Fine to wear whatever. Make reservations at a somewhat nicer place? Maybe change into something a touch dressier, but no need to be formal (unless it's a very specific type of high-end restaurant, you will know the difference). Light summer dresses are perfect for nicer dinners, and sleeveless/above the knee ones are perfectly fine.

AND the church rules are about covering up, not formality. Wear a gigantic t-shirt, a scarf as a skirt, whatever. Sometimes people get confused and think they have to "dress up" to visit churches. Nope, just cover knees and shoulders and you are good to go.

Here in the hot and humid south (currently 87, 85% humidity) I have discovered what I call walking dresses. I have several very comfortable but beautiful sleeveless dresses with pockets. Amazon has some beautiful colors and patterns around $20 or less. I also have a skirt that hits just below my knees. Cooler than shorts! I might add a shawl for cooler evenings,or for churches that forbid bare shoulders.

If its hot shorts and tank tops aren't cool. Loose dresses are cooler -but not practical for travel. I normally wear a loose mid-calf skirt and a loose shirt which covers my shoulders. Wear either a fabric that evaporates well -I used to always wear silk but now use the modern fabric designed for gym wear - the stuff is brilliant for wicking moisture.

There is a reason that traditional dress in deserts is long and loose for both genders. Its more practical

You can wear whatever you want in most restaurants and public places such as museums and shopping. But... you will most likely be out of place. Do you wear them in Rochester? Especially when I am on vacation I enjoy dressing more than very casual. Just me. A cool casual classy linen or cotton dress will be more comfortable and acceptable. Keep a scarf or shawl for covering knees if necessary.

Enjoy

Lorie

I'm in agreement with Lorie. I try not to look like the people of WalMart when traveling. Also, as mentioned, there are ways to dress that look nicer and is actually cooler.

The first time we were in Italy was on a school trip back in 1966. We were there in August and the temps in Rome reached 103! Back then, the hotels were not air conditioned, nor were most public buildings.

Salerno is part of the Amalfi coast and will be super crowded with tourists this time of year.

We are in Italy right now. I saw some athleisure wear in Rome but not much. Shorts and lightweight sleeveless tops were very common, even among Italians, in Rome, Florence and the villages we’re visiting in Umbria. With the heat, we’ve tended to shower in the evening before dinner. I brought several dresses. Men are OK in shorts with a polo or other collared shirt in restaurants.

Lightweight linen sun dress for women and sandals and linen buttondown style shirt for men with linen shorts and casual not sporty sneakers or sandals will have you looking like a local (or a tourist that just went locally shopping) if that is the goal. Blue, White and Tan are most common colors of the summer.

Ath-leisure is not as prominent but the younger generation is often in branded tee shirts or sweatshirts
My wife noted regarding brand names and it was true, the Italians and other Europeans are often wearing American brands where as American tourists are more likely to wear Italian or European brands, which was kind of funny.

When it is 90 plus degrees even in St. Peter's you can wear most anything even though you should cover your shoulders, knees and mid-drift. I was there in May of this year and was 80, maybe 82 max and absolutely no dress code was enforced ; huge crowds. Tons of tank tops, shorts, skirts, etc...
I have been in not very hot weather and the code was enforced.
My family and I dressed per the code so not condoning not doing just saying they do not enforce it in hot weather. The dress code for churches/places of worship is more about respect than the written rules so best to treat all churches the same, enforced or not.

Other tourist attractions (no church), Restaurants you can wear anything, same as for anything else small or large city that will not change.