Ok I realize that there are 4 seasons in a year and all. And however that was something that was taught to me in kindergarden or so I have forgotten when these seasons are? For example if someone says that a particular tent is for season 3 what does that mean exactly?
3 season tent' means its not for deep winter conditions. Spring, Summer, Fall duty mainly. They WILL work in the cold only(meaning no big 50mph+ wind, snow, etc), but..
..theres going to be some mesh used in the main tent body(under the fly) via panels and windows for ventilation. Tents can get hot fast while out in the sun in mild conditions. Because of this, its usually impossible to stop wind blown spin drift snow from coming in, via being wind sweeped up under the rain fly(be there done that). Nor stop cold air from coming thru otherwise, making your bags job somewhat harder.
..they aren't as strong(less poles, less guyouts, etc) since they aren't designed for big winds, snow, etc. but this also means they weigh measureably less and less bulky to pack.
Std 2-wall 4 season tents have the ability to shut down most, if not all ventilation with solid ripstop(or coated) type fabric zip-in panels(over the otherwise sewn in mesh panels/windows) and windows. =Warmer and no spin drift coming in.
4 season tents usually have more poles, that are also usually attached via velcro loops underneith the fly, to guyouts on outside surfaces(at corners and pole crossings, typically) at key points that are guylined out to stakes in the ground.
4 season tents are typically heavy and bulky, unless you get the very best, like highend singlewall designs(typically are waterproof breathable, but not always). Singlewalls are lighter, go up faster, less bulk. They're usually placed in the next class, called "mountaineering" duty(for summit attemps on stuff like K2, Everest, etc, but 4 season 2-walls do fine at the lower base camps).
Great explanation regarding them.
