First trip to Italy - Venice in late August or late October?

It's is not really much of a big deal.

Your overall enjoyment won't in any way be diminished by individual businesses being closed for summer vacation.

Go for it. Enjoy.

Thanks, I will certainly enjoy it either way.

But since I have a choice, which is better?

August average temps ...
Venice: 18c to 27c
Florence: 18c to 31c
Rome: 18c to 30c

September average temps ...
Venice: 15c to 24c
Florence: 16c to 27c
Rome: 16c to 27c

October average temps ...
Venice: 10c to 18c
Florence: 12c to 21c
Rome: 12c to 23c

November average temps ...
Venice: 4c to 11c
Florence: 7c to 15c
Rome: 8c to 18c

Sep/Oct generally provide better conditions for travelling than Aug/Nov. Personally I would prefer the certainty of heat over the possibility of quite cool. It certainly makes the gelato stops more enticing.

August will be hot. October should be nice and you will not have to worry about whether or not your lodgings have air conditioning, or how well it works. Most of my trips to Venice have been in December, January, and February. There were always some pleasant days, so even in the dead of winter, its great.

Haha...yeah, so it's really a toss up and a matter of preference.

I think I might just stick with August, since cold, rainy, and crap won't be a possibility. Super hot and muggy sounds bad, but at least it wouldn't ruin the whole day.

weather.com has historic data easily available ---in 2016 at the end of Oct the high temps were 60ish the low 50s-upper40s

With August being prime US tourist travel time, I would expect most places would be open.

Any reason you did not choose the 8-18 start date ( $300 discount)?

We have always enjoyed Venice off-season. In fact, our favorite month there is December. I would take cool over hot any day, but it might depend on what you are used to and how you react to heat. Also, August will be far more crowded.

Don't worry about closures. Venice will offer plenty of opportunities to shop any time of the year.

Thanks for the reassurance about the closings. I've been worked up over it actually.

I really like the prospect of 50 F to 70 F or so weather better than 91 F though.

I just remember how bummed I was in New Zealand when it went cold and rainy in November and vowed I'd never let that happen again.

I always go to Italy in late September early October...but later in October is very pleasant...and less crowded than August...

My first trip to Italy was mid-October. I needed a fan to sleep comfortably in Venice and was grateful for the AC in florence.
Since then, I've been to Venice and to Rome 3 times, all in February. Even in mid-winter, there were lots of sunny days, very few rainy ones. I'd choose October over September - less heat, less humidity, less tourists.

This year I was in Venice in February and took a walking tour of one of the coldest, windiest areas on a chilly, overcast day. It just made the hot chocolate rest stop all the better.

I have had too many friends tell me how miserable they were in Italy in summer. I also hate hot! If i had to choose between hot and cool, is choose cool any day.

We have only been in Venice in April (5 days) and October (a full month in 2013 and a week in 2015). It was not cold or rainy at all---I wore short sleeves most of the time, with a light jacket for evening. But of course any given year could be different.

What I would never do is go during the summer. Too hot and even more crowded than later.

The Venice Biennale is in October, a good reason to go then if you like edgy modern art.

Of course November is the middle of spring in New Zealand, equating to May in Europe/North America.