Today's Longest Or Shortest Daylight?

Growing up about 38.8 degrees north of the equator, in northern Virginia, we always referred the first day of summer as the Summer Solstice- the longest day of sunlight in the year - which occurs today on June 21st. With roughly 85% of the land mass and 90% of the world’s population in the Northern Hemisphere, it is understandable we might forget about the people living south of the equator. Sorry folks living Down Under including in Australia and New Zealand. They are experiencing their shortest day of the year known as the Winter Solstice.

According to NOAA SciJinks, “You may have noticed two special lines of latitude on a globe of the world: One in the Northern Hemisphere called the Tropic of Cancer at +23.5° latitude and one in the Southern Hemisphere called the Tropic of Capricorn at − 23.5° latitude. These are the latitudes where the Sun is directly overhead at noon once a year. In the Northern hemisphere, on the Tropic of Cancer, that is the Summer Solstice, usually June 21. In the Southern Hemisphere, on the Tropic of Capricorn, that is the Winter Solstice, usually December 21. These solstice days are the days with the most (for Summer) or fewest (for Winter) hours of sunlight during the whole year.”

So if June 21st is the longest day of sunlight in the Northern Hemisphere why isn’t it usually the hottest day of the year? Well it takes some time for the oceans to absorb the heat and release it back into the atmosphere. The heat wave exceeding 100 degrees F. in many areas including the Western Untied States occurred during the spring so we cannot expect this summer to get any cooler.