Is the date of "Li Qiu" fixed? "Li Qiu" is one of the 24 solar terms in China, indicating the beginning of autumn. It usually falls on August 7th or 8th in the Gregorian calendar. However, some people may wonder whether this date is fixed or not. The answer is no. "Li Qiu" is determined by the position of the sun, which changes every year due to the rotation and revolution of the earth. The precise moment of "Li Qiu" is when the sun's longitude reaches 135 degrees. This occurs at different times each year, and the earliest and latest dates of "Li Qiu" in the Gregorian calendar can vary by more than 10 days. In fact, the same is true for all the 24 solar terms. They are based on the astronomical observation and the ancient Chinese wisdom of nature. They reflect the changes of the seasons, the climate, and the agricultural activities throughout the year. As such, they are not only important for the traditional festivals, but also for the modern life and culture in China. To sum up, "Li Qiu" is not a fixed date, but a dynamic cycle. It reminds us of the impermanence and diversity of nature, and encourages us to adapt and appreciate the changes of the world. By observing and celebrating the solar terms, we can deepen our connection with the natural environment and enrich our cultural heritage.