What's the local weather like in Nice, Cannes and other cities in southern France 10? Do I need to wear a down jacket?

I once went to Nice in mid-June165438+1October, and it was already very cold, but it didn't snow because it was a seaside city like Paris, but it was also very cold because of the sea breeze. Because in France, most indoor places are turned on when it is cold, so I suggest not to wear too thick inside, and wear a thick coat and down jacket outside, so you can take it off indoors. It won't be cold in the street. In addition, it is recommended to bring a stove when you go out on the street, preferably one with insulation. I was in Nice at that time, because the wind was strong and cold, so I didn't bring a stove. My forehead was cold and I felt a little cloudy. Later, I immediately bought a set of heat preservation stoves and felt much more comfortable.