When is the colorful willow green flower red?

Spring, the first of the four seasons, refers to the period from beginning of spring to long summer, including solar terms such as beginning of spring, rain, fright, vernal equinox, Qingming and Grain Rain. Spring represents warmth and growth. In spring, the qi of yin and yang begins to change, and everything germinates and grows with the rise of yang. As far as solar terms are concerned, spring in China begins in the beginning of spring (February 2-5) and ends in the long summer (May 5-7). In Europe and America, spring begins at the vernal equinox in China and ends at the summer solstice. In Ireland, February to April is designated as spring. At present, the method of "waiting for average temperature" proposed by modern scholar Zhang Baokun is often used to divide the four seasons in China. Taking the five-day average temperature as the standard, the five-day average temperature after winter passes 10℃ and begins to enter spring. When the temperature is higher than 22℃, it means the end of spring and the beginning of summer.