In the Northern Hemisphere, the June solstice (aka summer solstice) occurs when the Sun reaches both its highest and northernmost points in the sky.
In temperate regions, we notice that the Sun is higher in the sky throughout the day, and its rays strike Earth at a more direct angle, causing the efficient warming we call summer. Because the sun is highest in the sky on this day, you’ll notice that your shadow (at noon) is the shortest it will be all year.