Sunny weather in May is called "Gogatsu-bere" (May clear skies), but the rainy season has already started in Okinawa, and it rains every few days in May, and there are periods of continuous rain in Honshu as well. It is called the "early rainy season" because it is before the full-scale rainy season begins, but you should actually be careful of dry skin during this time !
Regarding the "early rainy season," the forecasting term used by the Japan Meteorological Agency is "the beginning of the rainy season," and is described as "unsettled weather that appears before the rainy season."
https://www.jma.go.jp/jma/kishou/know/yougo_hp/kisetsu.html
Also, Yahoo! Weather reports that the amount of rainfall in Tokyo in April is 1.7 times the average, and that this is already the beginning of the rainy season. It also says that the rain will continue for several days from Wednesday, May 11th, the beginning of the week, so this may be the beginning of the rainy season .
During the rainy season, the humidity is high and the skin tends to be sticky, so moisturizing may seem out of the question, but in fact, the skin around the mouth and eyes tends to become dry. Even people with oily skin tend to have temporary dry skin after shaving, and do you feel your skin become tight or sting after shaving ?
In addition to ultraviolet rays, this is a season when you tend to sweat slightly, so if you do not blow off your sweat frequently, the sweat will evaporate and dry out your skin, and even indoors, using the air conditioning's dry function or setting the temperature slightly higher will dry out your skin.
Keep a moisturizing gel on hand and apply it whenever you feel like it. We recommend that you moisturize your skin a little more if you have razor burn . However, creams can leave a sticky feeling for a while, so we recommend a gel with nano-sized ingredients that penetrates the skin quickly !