Summer 2017 officially began at 12:24 a.m. on June 21.
Wednesday is the summer solstice across the Northern Hemisphere, the day with the longest span of sunlight. In contrast, it is winter in the Southern Hemisphere. This occurs because of Earth's tilt as it relates to the sun.
The Northern Hemisphere – locations north of the equator – is tilted towards the sun.
Beginning tomorrow, days will become shorter as we head through summer and look forward to the cooler temperatures that come with fall. This culminates with the Autumnal Equinox on Friday, September 22nd.