hey hey fstuart24
we were there first week of october several years ago, the weather was great. a week later there was a festival/celebration "retour des alpages", this year is october 11, 2025. (annecy-ville.fr/ return of the alpine pastures). the cows/animals return down the mountains to their warm stables until the next summer.
have no clue what will be open/closed in chamonix haven't been there. absolutely loved annecy, the lake & beautiful mountain views with snow capped top, city center shops and market days, restaurants. it's up to you about worthiness, i go to make my own opinion of new places, this hit the spot,
it was quiet and not that crowded when we went but nowdays i'm amazed at how many people mention it as a place to visit. at top of page in search box type in annecy, filter by date and lots of info there, you decide. enjoy & have fun
aloha