Reasons of the seasons The reason they invented seasons is because then you can classify what time of year it is. There are more reasons to have seasons like because some countries are dark some of the countries are bright some of the other countries are light and some other countries are kind of dark. When the Earth rotates then one side of the Earth is darker and one side of the Earth is bright so dark makes it cold and bright makes it warm right now New Hampshire is getting closer to the sun and even closer.