Two important factors that affect the climate of North Dakota are the angle (slant) of the sun’s rays and the hours of sunlight. The tilt of the earth on its axis and the rotation of the earth around the sun cause the length of day and the angle of the sun’s rays to be different during different times of the year. These factors result in four separate seasons: summer, fall or autumn, winter, and spring.
Figure 71. Seasons. North Dakota has four distinct (very different) seasons. (SHSND-ND Studies)