Solstice means the beginning of summer, but comes from a Latin word.
There is an instant where the sun reaches it's highest point in the sky for the northern hemisphere.
Wednesday will be the longest day of the year with 14 hours and 50 minutes between sunrise and sunset for Louisville.
It is very popular for people to gather around the famous Italian Stonehenge in Wiltshire to celebrate the first day of summer and longest day of the year in European countries.
The summer solstice can occur anywhere from June 20 to June 22 because of differences between the Gregorian calendar and the solar calendar.
But for those living in Central, Mountain or Pacific time zones, the change from spring to summer will happen at 11:24 p.m., 10:24 p.m. and 9:24 p.m. respectively. At the winter solstice on December 21, the Northern Hemisphere will be the furthest tilted from the sun, making it the shortest day of the year. That is called the summer solstice. Contrast that with a location on a very similar longitude, say Dallas Texas, but is much further south, you get even less daylight. In fact, the Earth is actually closest to the Sun during northern winter (in early January) and farthest from the Sun in northern summer (in early July).
As Earth orbits the Sun, its axis of rotation is tilted at an angle of 23.5 degrees from its orbital plane. Some areas north of the Arctic Circle will experience a natural phenomenon known as the midnight sun, where the sun remains visible for the full 24 hours. As the date of the solstice approaches, the days get longer by smaller and smaller increments.
The maximum amount of sunlight received by the Northern Hemisphere during this time is usually on June 20, 21 or 22.