Observing the Sky: Motion of the Sun and Stars - The Daytime Sky

The Earth's rotation and tilt not only give us the seasons, they also affect how the Sun and stars seem to move throughout the year.

We say the Sun rises in the East and sets in the West, yet this is only true on two days each year. During summer in the Northern Hemisphere, the Sun rises north of East and sets north of West. In winter, the Sun rises south of East and sets south of West. Only on the Spring and Fall Equinoxes does the Sun rise due (exactly) East and set due West.

When the Sun rises north of East, it passes higher through our sky on its way to the western horizon. Summer days are long because the Sun must travel through more sky before setting. The farther south the Sun rises, the lower it stays in our sky and the shorter the days. On the longest day of the year, the Summer Solstice, the Sun reaches its highest altitude in our sky at midday. At midday the Sun is due South and it crosses the meridian, an imaginary line that divides your sky into eastern and western halves. Each day after the Summer Solstice, the Sun's altitude at midday will be slightly lower until it reaches its lowest midday altitude on the Winter Solstice, the shortest day of the year.