Therefore near June 21st, the southern hemisphere is having its winter solstice because it "leans" away from the Sun.Īdvancing 90 days, the Earth is at the autumnal equinox on or about September 21st.
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. The opposite is true in the southern hemisphere, where the low sun angle produces short days. In addition, the high sun angle produces long days.
What this means is less sunlight gets scattered before reaching the ground because it has less distance to travel through the atmosphere. This situates the northern hemisphere in a more direct path of the Sun's energy. 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 is why the Earth's 23.5 degree tilt is all important in changing our seasons. But this distance change is not great enough to cause any substantial difference in our climate. This being said, the Earth is at its closest point distance wise to the Sun in January (called the Perihelion) and the furthest in July (the Aphelion). The Earth has an elliptical orbit around our Sun. Instead, the seasons are caused by the Earth being tilted on its axis by an average of 23.5 degrees (Earth's tilt on its axis actually varies from near 22 degrees to 24.5 degrees). If this were the case, it would be hotter in the northern hemisphere during January as opposed to July. The seasons have nothing to do with how far the Earth is from the Sun.