Seasons

As the earth travels around the sun, it's position relative to the sun changes. Since the earth rotates on a tilted axis and never chances this tilt as it circles the sun, there are times of the year where the northern hemisphere points towards the sun and times of the year where it points away from the sun. When we point towards the sun we get more light and heat. This area of the globe is warms. When we are pointed away from the sun we get less light and heat which cools off our area of the earth. This causes months on the where the same place on earth has different  temperatures. This is what we call seasons.

Summer begins in the north on June 21. This is the summer solstice. The sun is high in the sky and there are more hours of daylight than any other day. The shortest day of the year for the Northern Hemisphere begins Winter and is on December 21. On this day the sun is low in the sky and there are the least amount of daylight hours.

Spring begins when the earth begins to point towards the sun. This is the vernal equinox On March 20, the sun is directly above the equator giving us the same number of daylight ours as nighttime hours. Fall also has 12 hours of daylight and night. The autumnal equinox on September 23 is the time where the Northern Hemisphere begins to point away from the sun.