Science, Tech, Math › Science Summer: The Sunshine Season Summer Dates and Typical Weather Share Flipboard Email Print June 20, 2016 is the first day of summer. Don Mason/Blend Images/Getty Images Science Weather & Climate Understanding Your Forecast Storms & Other Phenomena Chemistry Biology Physics Geology Astronomy By Tiffany Means Meteorology Expert B.S., Atmospheric Sciences and Meteorology, University of North Carolina Tiffany Means is a meteorologist and member of the American Meteorological Society who has worked for CNN, the National Oceanic and Atmospheric Administration, and more. our editorial process Tiffany Means Updated November 04, 2019 Grab your shorts, swimwear, and SPF 30+ because summer is here! But what does that mean season- and weather-wise? What is summer? Summer, in a nutshell, is the warmest season of the year worldwide (with the exception of one or two tropical locations that also see balmy weather at other times of the year). When is Summer? The Memorial Day holiday is considered to be the "unofficial" start of summer here in the U.S. But summer isn't officially declared until the summer solstice, which occurs every June 20, 21, or 22 in the Northern Hemisphere (December 20, 21, 22 in the Southern Hemisphere). It runs until the next season, fall, begins with the fall equinox. On this date, Earth's axis points its innermost towards the sun. As a result, the sun's direct rays strike at the Tropic of Cancer (23.5° north latitude) and heat the Northern Hemisphere more efficiently than any other region on Earth. This means that warmer temperatures and more daylight are experienced there. When is the summer solstice? See the table below for a list of 2015 to 2020 summer solstice dates. These are the summer start dates you'll see marked on your calendar. But if you want to celebrate summer like a true meteorologist (or just want it to start as soon as possible) you'll want to observe it's start on June 1. Meteorological summer not only begins earlier, but it ends sooner too. It lasts for the 3-month period of June, July, and August (December, January, February in the Southern Hemisphere) and ends on August 30 (February 30). Year Northern Hemisphere Southern Hemisphere 2015 June 21 Dec 22 2016 June 20 Dec 21 2017 June 21 Dec 21 2018 June 21 Dec 21 2019 June 21 Dec 22 2020 June 20 Dec 21 (Astronomical) Summer Solstice Dates More: Astronomical vs. Meteorological summer - what's the difference? Summer Weather Summer's most treasured weather type is of course its higher temperatures. But even summer, a seemingly cheerful season, has a severe side. Extreme HeatHeat IndexDroughtsHail stormsThunderstorms One of the reasons storms become more intense during this time of year is because of the high amount of heat in the atmosphere which works to fuel convection (the heat exchange between the ground and air). Now that you know what summer's about, you're ready to enjoy it's activities, including swimming. But before you cannonball into the nearest pool, I should warn you about this...