if you can define winter you can use your definition to label your data and group by it.
I recommend that you study such data manipulation techniques from this excellent source.
https://r4ds.had.co.nz/
If you wish specific help on your own data, that we do not possess, then I ask you to please take some time to prepare a reproducible example (reprex)FAQ: How to do a minimal reproducible example ( reprex ) for beginners