So, we all know that there are many mods out there that add seasons to minecraft. I'm sure that a lot of people have suggested something like this, and based on the lack of this in CCNet, I assume they've all been turned down. I hope that my suggestion might get some support based on the nuances I'm going to add to it.
1. Every week, the seasons go from Spring, Summer, Autumn, and Winter.
2. I DO NOT suggest that these seasons affect plant growth, but perhaps there is some room for change there, but again, I personally do not suggest it.
3. The seasons simply work by changing the textures of blocks during those week periods during the daily server reset.
4. For things like weather and freezing, I would just not have water freeze at all except for where it normally does in certain biomes, and it perhaps rains a little bit more in spring and fall, and it snows in winter, but this snow is simply a weather effect and doesn't build up on the ground except for where it normally does in certain biomes.
5. In biomes where the weather is already different due to vanilla mechanics, I suggest several things. In all snowy biomes, everything stays the same except for winter, where it perhaps snows more. For deserts, there is no snow at all, but perhaps in the Spring or Autumn, depending on where it is in the world, there could be a lot of rain for monsoon seasons.
I think these seasons would be really neat just for the atmosphere of CCNet.