Well I'll do my best!
What creates a season is the amount of radiant energy in a location. As the Earth rotates on its axis around the sun different parts will receive higher and lower levels.
The reason Costa Rica only has two seasons is because of its location on the Earth. It sits between 8 degrees and 11 degrees North latitude, which is fairly close to the equator. Meaning that although the Earth is rotating on its axis at about 23 degrees it is in one of the warmest places on the Earth throughout the year. The climate system is based off of the trade winds and westerlies. The trade winds from the north blow northeast and the ones from the south blow south east, meeting near the equator, which causes the air to rise. As the rising air cools, clouds develop with rain.
Whereas in Maryland when the Earth rotates at some points the sun rays are less intense because of its location. As the Earth rotates, depending on the angle, it could be cooler or hotter. It has different variables than the zones Costa Rica lies in.
Read more about World Climates
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