When summer comes to Japan there are three things that suck. The heat, the humidity and the cicadas. It gets quite hot in Japan sometimes, albeit rarely, hitting 40C (104F), but generally snuggling between 30-40C. The humidity gets up to 95% and you just start to feel like a pulpy mess of human flesh drenched in liquid stink, grease and sweat. The humidity makes it difficult to breathe and leaves you feeling lethargic and just out of it. And then there is the triple whammy of the cicadas. These overgrown horseflies swarm any trees in the general vicinity and screech and whelp all day long. They generally start up when the sun comes up and get their loudest in mid-day.
Now to say it's loud is an understatement. Recently a friend used his decibel meter to measure it and it was hitting 90 decibels. 90 decibels is like hearing a train whistle at 500 feet away. It's quite loud and it's constant. If there is a tree near your place you are going to be inundated by cicadas. Now you might think Japanese people hate them, but actually I've heard from lots of people here that they sound pleasant and remind them of summer. They even have onomatopoeia for the different types that debut throughout summer.
Personally I hate them. I think they are noisy and I am driven mad by their deafening sounds. In fact I have gotten so irritated that at one point I took a 4 meter laundry pole and started banging it against all the trees in my area to get the cicadas to leave. And they did leave for about 30-minutes after which they returned and started again with their annoying sound. Until you experience cicadas in a Japanese summer you just don't know how close to the edge of madness these pests can drive you.