What do you mean the first month is a rainy month?

Ancient solar terms were called "Qi", and each month contained two Qi, the former was called "Solar Term" and the latter was called "Zhong Qi". The twelve solar terms are beginning of spring, Jingzhe, Qingming, Changxia, Mangzhong, Xiaoshu, beginning of autumn, Bailu, Hanlu, beginning of winter, heavy snow and slight cold. The twelve middle qi are rain, vernal equinox, Grain Rain, Xiaoman, summer solstice, summer heat, early summer heat, autumn equinox, early frost, light snow, winter solstice and severe cold. Later generations referred to solar terms and neutral gases as solar terms. According to the ancient regulations, every month is represented by the qi contained in it. The solar terms and distribution of qi in each month are as follows: spring, beginning of spring, the first month, solar terms, summer, long summer, April, solar terms, rain, the first month, stingy, full of gas, April, gas shock, February, solar terms, mango, May, solar terms, vernal equinox, February, zhongqi, summer solstice, clear gas, March, and summer solstice. Monthly solar term autumnal equinox August mid-air winter solstice1/month mid-air cold dew September solar term slight cold1February solar term first frost September mid-air cold1February mid-air.