Scientific Reason for the Seasons 

Week of September 19 – September 25, 2021

baltimore woods staff photo of morgan-ingraham

by Morgan Ingraham, Naturalist

After moving cross-country from the deserts of California, I’ve experienced the drastic seasonal changes of Central New York. And during this transitional season of autumn, I began to wonder…why do the seasons change? And why are they so different across North America?

The answer lies in the tilt of the earth on its axis at 23.5 degrees. The tilt brings the Northern Hemisphere closer to face the sun in summer months, and obscures it from the sun in the winter months. The opposite is true for the Southern Hemisphere. The earth tilts the Southern Hemisphere away from the sun in summer and facing the Sun during winter. Latitude (north to south) is what matters for seasons. That is why so many animals migrate south for the winter!

There are other differences that contribute to seasons. The Northeast has much more drastic seasonal changes than the West Coast. This is not due to the Earth’s tilt, but instead due to prevailing weather patterns and geography. Because these weather patterns move from west to east, the West Coast climate is kept more stable by the Pacific Ocean and the Northeast receives weather from across the Great Plains, resulting in snowy winter storms. Mountain ranges and elevation are also important for seasonal climate changes. Higher elevations are colder, windier, stormier, and wetter than sea-level elevations. 

So as we continue to tilt our way around the sun, take a moment to think about the connections between our weather here and all across the world.


The changes of seasons (United States) –

Why do we have different seasons? –

Specific heat of water  (why living near the ocean has more stable temps than inland) –

Mountain effects on climate video –