Observe: A Closer Look at Seasonal Differences

Do you recall why a model globe has the Earth angled slightly off to the side? Remember that is because the Earth is tilted at an angle of 23.5° off the perpendicular to the plane it travels in around the Sun. This plane is called the ‘Plane of the Ecliptic’.

Be thankful for that tilt! Without it, we would not have the seasons we enjoy here on Earth.

The revolution and the tilt of the Earth tip different parts of the planet towards and away from the Sun. Recall that when the Northern Hemisphere is tilted towards the Sun, it has summer, but the Southern Hemisphere has winter.

By the time Earth travels six months across to the other side of the Sun, the Northern Hemisphere is tilted away from the Sun. That is when we have winter and, therefore, the Southern Hemisphere will have summer.

Regions around the Equator do not have as much change in seasons as other parts of Earth, but all parts of the Earth have seasonal changes. For the Polar Regions (the areas at the top and bottom of the Earth), the seasons change the amount of daylight and darkness they experience more than the temperature.

During the winter, in the Northern hemisphere, the path of the sun is much lower in the sky and there are fewer daylight hours.

At Winter Solstice, the Sun is lowest in the sky. This is when the poles have the least amount of sunlight. The northern parts of Canada receive almost 24 hours of darkness. For the rest of Canada, Winter Solstice is the shortest day of year. The opposite is true in summer.

During the summer, the path of the Sun is much higher in the sky in the Northern hemisphere. This means the Sun spends more time in the sky; thus, the days are longer. At Summer Solstice, the Sun is highest in the sky and we have the most amount of sunlight. It is the longest day of year.

The most northern parts of Canada receive almost 24 hours of daylight during Summer Solstice. “Sol –stice” means the “Sun stands still”.

Day and night are the same length of time at the Autumnal and Vernal (Spring) Equinox. “Equi-nox” means “Equal night".

  Check Your Answers

Observation Answers

Season	Earth's Position Around the Sun
Winter
Spring
Summer
Autumn

Question	Observation
For what fraction of the day is the person in the light in the winter – more than half, less than half, or about half?	Less than half
For what fraction of the day is the North Pole in the light during June?	During June, the North Pole is in the light all day long (24 hours).
Explain the reason for the temperature difference between summer and winter.	In the summer, the Northern hemisphere is tilted closer to the Sun so it is warmer. In the winter, the Northern hemisphere is tilted away from the Sun so it is colder.
Explain why the days are longer in the summer than in the winter if Earth takes the same amount of time to complete its daily rotation.	Days are longer in the summer because the angle of the Sun is higher in the sky. Sun takes longer to move over the horizon, and so we get more daylight.