The summer solstice occurs around June 21 in the Northern Hemisphere, marking the longest day of the year. This event happens when the Earth's axial tilt is closest to the sun, resulting in the sun reaching its highest point in the sky. During the summer solstice, many cultures celebrate with festivals and rituals, recognizing the importance of sunlight for agriculture and life. The opposite occurs in the Southern Hemisphere, where the winter solstice takes place, leading to the shortest day of the year. Both events are significant in understanding the Earth's seasonal changes and the relationship between the Earth and the sun.