This year’s Winter Solstice will occur on Dec. 21. Many ancient sites, like Newgrange in Ireland, pictured, were built to be aligned with and track the Winter Solstice. Photo by Bethany O’Hagan The ...

The start of summer is here. Although parts of California have already experienced triple-digit temperatures, the new season doesn’t officially arrive until the summer solstice — an astronomical event ...

Summer has officially begun in California. The start of the new season is marked the summer solstice — an astronomical event that marks the longest day of the year. Past this point, the days will get ...

The winter solstice marks the first day of winter in the Northern Hemisphere. The solstice happens when the Earth's axis is tilted farthest from the sun, resulting in the shortest day of the year.