Having a town filled with trees and bushes and flowers and stuff, I learned a few things about snow.
For one, the different snowpeople take different times to melt. The bingo snowman takes 4 days to melt, snowboy takes 3, snowmam takes 2, snowtyke is only there the day that you make it.
I learned this because the only snowcreature I ever succeeded in making was a snowtyke (there's not much empty ground in my town, it's all filled with trees) and it disappeared the next day.
Also, when snowpeople are built on top of flowers, they kill the flowers. Don't build one on top of a hybrid is my advice to you.