Summer Solstice 2026: Today, 21 June 2026, marks the Summer Solstice, the longest day of the year in the Northern Hemisphere. Caused by Earth's 23.5-degree axial tilt, this astronomical event brings the maximum number of daylight hours and the shortest night of the year. Interestingly, it coincides with International Yoga Day, linking a significant scientific phenomenon with themes of balance and well-being. While India experiences slightly longer days today, the hottest days of summer usually arrive later due to a phenomenon known as thermal lag.