In 2004 we visited Aix-en-Provence in August. It was hot. Very hot.
One thing I remember was the constant chirping of the cicadas. It seemed to me that they sang all day and all night.
In 2005 we moved to Bordeaux. A couple years ago we visited some town about 50 miles south of Bordeaux in the summer and heard cicadas. We never used to hear them in Bordeaux. It wasn't hot enough.
Then last summer we heard them for the first time in a nearby tree from time to time.
This year we hear them in the trees just across the building site from our flat.
It's surely not a good sign, but I like to hear them nonetheless.