https://www.asahi.com/ajw/articles/14972048
Last month was the hottest July in Japan in more than a century, according to analysis by The Asahi Shimbun of average temperatures since 1898.
You are a lot further north in JP, so in the summer months Japan is literally closer to the sun.
That kinda makes sense. However, in my home country (Finland), which is further north I think, the sun is quite gentle in the summer season.
Ah, well then you start talking about the difference in the surrounding oceans, winds, humidity, etc. the significant change in longitude comes into play there.