ASK THE METEOROLOGIST
“Why does the weather change every season?”
6th grades in Mrs. Schultz’s class at St. Mary’s School
The main reason for the seasons is the tilt of the Earth’s axis! The Earth is tilted at 23 degrees as it orbits around the sun. This changes how high the sun is in our sky year round! Let’s break it down.
We’ll start with the Autumnal Equinox, or the start of fall. This is always in September every year, and the point at which the most direct rays from the sun are positioned over the Equator. As earth continues orbiting around the sun, three months later we enter winter. This is known as the Winter Solstice, the shortest day of the year. At this point, the sun angle is very low in the Northern Hemisphere. This is because the sun’s rays are perpendicular, or shining most directly over 23 degrees south latitude. This is the Tropic of Capricorn. For the Southern Hemisphere, it is summer. Our days stay cold because the sun angle is low and the days are short.
Three months later, as we continue our treck around the sun, we enter the Vernal Equinox. This is the start of spring. The sun is most directly over the equator by this time of year (starting to move further north). Our days begin to get longer and our temperatures warmer as we round out winter and approach summer.
Three months later we nearing a full circle around the sun. The Summer Solstice in June is the start of summer and also the longest day of the year. Our days are long in the summer and the sun angle is high. The sun’s most direct rays are over the Northern Hemisphere, more specifically the Tropic of Cancer or 23 degrees north latitude.
Because our earth stays tilted at approximately 23 degrees and we make a full orbit around the sun in 365 days, we have four different seasons that define the changes in our weather!
Meteorologist Alyssa Caroprese