WEST MICHIGAN - While we may have welcomed in meteorological summer June 1, astronomical summer officially arrives today at 5:14 A.M.. This day contains the most daylight with about 15 hours and 21 minutes! The days gradually start to get shorter beginning Wednesday. It's known as the summer solstice, the exact time and point when the sun is 23.5 degrees north of the equator. After this, the sun begins to make its trek southward toward the equator, arriving there in September for the equinox.
Recall that the seasons have nothing to do with how far the Earth is from the Sun. If this were the case, it would be hotter in the northern hemisphere during January as opposed to July. Instead, the seasons are caused by the Earth being tilted on its axis by an average of 23.5 degrees.
The Earth has an elliptical orbit around our Sun. The Earth is at its closest point to the Sun in January (called the Perihelion) and the furthest in July (the Aphelion). But this distance change is not great enough to cause any substantial difference in our climate. This is why the Earth's 23.5 degree tilt is all important in changing our seasons. Near June 21st, the summer solstice, the Earth is tilted such that the Sun is positioned directly over the Tropic of Cancer at 23.5 degrees north latitude. This situates the northern hemisphere in a more direct path of the Sun's energy. In addition, the high sun angle produces long days. The opposite is true in the southern hemisphere, where the low sun angle produces short days. Furthermore, a large amount of the Sun's energy is scattered before reaching the ground because the energy has to travel through more of the atmosphere. Therefore near June 21st, the southern hemisphere is having its winter solstice because it "leans" away from the Sun.
With the sunlight being almost overhead, the rays are intense. It's very easy to sunburn this time of year. By September, the sun will be directly overhead of the equator with the rays being far less intense and the daylight hours growing shorter. Perhaps the arrival of summer this week is appropriate! We expect hotter temperatures much of this week and mainly dry conditions. See the forecast model heat index values below for Tuesday. HEAT ADVISORIES are in effect all day along with a CLEAN AIR ACTION DAY!
Get the complete West Michigan forecast at www.fox17online.com/weather.
