中华万年历

夏至是二十四节气中的第10个节气，也是夏季的第四个节气。每年公历6月21日或22日，当太阳到达黄经90°时为夏至。夏至这天，太阳直射北回归线，是北半球一年中白昼最长、黑夜最短的一天。"至"是"极"的意思，夏至即夏天到了极点。夏至过后，太阳直射点逐渐南移，北半球白昼开始缩短，黑夜开始加长。夏至是一年中阳气最盛的时节，气温高、湿度大、不时出现雷阵雨。在中国传统文化中，夏至与冬至一样，都是重要的节气，自古就有庆祝夏至的习俗。夏至时节，我国大部分地区气温较高，日照充足，农作物生长旺盛，也是农业生产的关键时期。

Summer Solstice (Xiazhi) is the 10th solar term among the 24 solar terms and the fourth solar term of summer, occurring around June 21-22 when the sun reaches 90 degrees celestial longitude. On Summer Solstice day, the sun directly illuminates the Tropic of Cancer, making it the day with the longest daylight and shortest night in the Northern Hemisphere throughout the year. "Zhi" (至) means "extreme" - Summer Solstice signifies summer reaching its extreme point. After Summer Solstice, the sun's direct point gradually moves southward, Northern Hemisphere daylight begins shortening while nights begin lengthening. Summer Solstice is the period of most abundant yang energy throughout the year, with high temperatures, high humidity, and occasional thunderstorms. In traditional Chinese culture, Summer Solstice, like Winter Solstice, is an important solar term - there have been customs celebrating Summer Solstice since ancient times. During Summer Solstice, most parts of China experience relatively high temperatures with abundant sunshine - crops grow vigorously, making it also a critical period for agricultural production.