Japan seems to have entered rainy season, which is earlier than average year.
In Japan, rainy season is called "Tsuyu" or "Baiu", whose literal meaning is "plum rain".
There being a few theories on the origin of the name "Tsuyu", the most convincing one is that plums get ripe during rainy season, around June to July.
More confusing thing is that we used to call Japanese rainy season "Samidare", whose literal meaning is "May Rain" or "May Water Drip".
This is because we used to follow lunar calendar to describe seasons and May of lunar calendar coincides with June or July of Gregorian.
～ Vocabulary related to Japanese Rainy Season ～
梅雨前線 ： a seasonal rain front
停滞前線 ： a stationary front
寒気団 ： a cold air mass
暖気団 ： a warm air mass
モンスーン ： monsoon
気象庁 ： Japan Meteorological Agency (JMA)
温帯低気圧 ： extratropical cyclone
降水（量） ： precipitation
傘 ： umbrella
アジサイ ： Hydrangea
カタツムリ ： snail
じめじめした（湿気の多い） ： humid
黴 ： mold