What causes the seasons?
The Earth is not aligned straight up but is actually on a tilt of around degrees, with our North Pole pointing directly to the star Polaris, making it visible throughout the Northern Hemisphere.
As Earth orbits the Sun on the ecliptic plane, this tilt causes the different hemispheres to experience varying degrees of sunlight at the same type of year, depending on which one is pointed closer to the sun and which one is pointed away.
The rising and setting Sun
Much like the moon, the Sun will often take different paths through the sky. As days get longer in the summer, the sun rises more and more north in the sky until the summer solstice. The more north the Sun rises in our local sky, the longer path it appears to take over it. The opposite is true in the winter— the Sun rises more and more south until the winter solstice.
Special Events
Solstices
A solstice occurs when the Sun has reached its maximum or minimum time in our local sky. During the Northern summer solstice in June, we experience the longest day of the year. This also means that the sun rises and sets at the most extreme north of due east, giving it a longer path across the sky.
Conversely, during the Northern winter solstice in December, we experience the least amount of daylight hours of the year. This time, the sun rises and sets at the most extreme south of due east, giving it a shorter path across the sky.
Equinox
An equinox is a term used to describe when day and night are approximately the same length. During an equinox, the sun rises precisely due east in our sky and sets precisely due west. There are two major equinoxes that we experience in the Northern hemisphere, the Northern spring equinox in March and the Northern Fall equinox in September.