The summer solstice is here. What to know about the longest day of the year

The summer solstice marks the longest day in the Northern Hemisphere and the start of astronomical summer, while the Southern Hemisphere experiences its shortest day and the beginning of winter. Solstices occur due to Earth's tilt, causing unequal distribution of sunlight. Equinoxes, conversely, bring equal day and night, with the sun directly overhead at the equator.