This is my chiken tikka theory of how season occur.

Take a chicken tikka stick. (you have seen them right? a few pieces of raw chicken is pierced into a stick)

Now ask yourself the question. How to get it minimally and maximally heated up by the fire from sun. If its minimally heated its winter and if its maximally heated its summer.

Now there are 3 primary parameters that influence the situation. One is called distance from the oven that sun is. Two any change that can be made to this distance is governed by two parameter. one when along a particular direction when we look at the oven how far it is? That distance can be changed a lot due to relative motion of earth and sun. Lets say therefore we will hold the chicken stick quite straight so it goes as straight as we stand on a given location on earth. Thats called a perpendicular in some poor mathematicians dictionary.

So you are naturally interested to know how far above you can the sun ever be? You have taken for convenience to hold the chicken stick up, perpendicular. So in the periodic motion (YES) of earth around sun, the sun resides at two extremes in the perpendicular chicken stick direction. The minimum distance is called a winter solstice and the maximum distance is called a summer solstice. As is obvious because its a periodic motion sun can oscillate wrt us only in two limiting height. These minimum and maximum heights are whats called solstices. (Because here the sun earth distance changes direction, it goes more and more OR it goes less and less)

So given that sun as a oven can only be as far as 152 million kms or as close as 147 million kms, the two solstices give a better description of when to derive maximum energy or minimum energy. That is apart from 3.4% variation in distance (152-147 is about 3.4% of 152 or is it the other way?) there are two situations when the distance still varies, much less compared to that 3.4% that gives a much better sensation of summer and winter, than the large 3.4% variation.

There still is another parameter. Its called the equinoxes. [A situation when night and day are for equal length of time]

Just like the solstices, think another situation. You are holding up a chicken stick up, exactly like you are standing. Now mother earth is concerned about giving you a little more warmth or comfort of cold as you may or may not demand. Earth like a true mother will twist towards or away from sun, the fatherly oven. That generates another very small fraction of total distance from the oven, like the solstices a small fraction compared to actual total distance or its variation.

So because of this twisting of earth (which can be maximum of 23.44 degree angle of earth wrt Sun towards or away from it) the chicken stick is now a little more away from sun teh oven, or a little closer to oit.

So because the total distance of sun and the variation in this total distance is fixed, what cause the chicken feel the summer and winter is the little variations called solstice and equinoxes.

So solstice is a elevation of sun directly above earth’s point and equinox is a twisting towards or away from sun of earth.

These two parameters actually give the sensation of summer and winter although fractionally very small compared to the first parameter, the actual distance.

Does this also explain why perennially elevated locations like mountains get a lotta snow fall ? There is much more. eg the earth’s core has metals, they radiate, the fluids radiate and conduct heat and so on. The elevated locations do not get much of the heated up earth. But I am out of much knowledge here.