Annecy heat in July?

Don't know what you consider hot. We were there in mid summer and thought it was hot.
I'd suggest looking up average highs and lows for the period when you'll be there, as acraven has provided.

I found it very hot indeed. The record high temperatures for July and August are about 100F. Those are outliers, of course, but July isn't what I'd call a moderate month.

The website timeanddate.com is a good source of actual, historical, day-by-day weather statistics going back about ten years for most places travelers want to visit. Checking out that information is a good way to see how unpleasant (or not) things might get.

Annecy July 2021: https://www.timeanddate.com/weather/france/annecy/historic?month=7&year=2021

Annecy July 2020: https://www.timeanddate.com/weather/france/annecy/historic?month=7&year=2020

Annecy July 2019: https://www.timeanddate.com/weather/france/annecy/historic?month=7&year=2019

Annecy July 2018: https://www.timeanddate.com/weather/france/annecy/historic?month=7&year=2018

Annecy July 2017: https://www.timeanddate.com/weather/france/annecy/historic?month=7&year=2017

Yes, it gets hot, but it should cool down at night even on hot days, making sleeping OK (at least in a flat with several windows. A small hotel room facing the wrong direction could be unpleasant). There may be exceptions, the timeanddate website is great to give you an idea.
Conversely, it can also be cool and rainy. It is not predictable.

I was very glad I had an air-conditioned hotel room.

Thanks, all. Yes, I should have explained what is “hot” to me— I’m from SC, so I am used to 90-100* from June-sept. :) I just wanted to know if I can wear “summer wear” :)

I appreciate your replies.
-j