The tales of Jack Frost are found in various folklore like in Anglo-Saxon, Norse, German and Russian. In all of them he came to be in different ways. The Russian Jack is actually another form of Grandfather Frost, while when looking into German lore those two are completely different personas.
The most famous of the entities is said to be friendly sprite. He doesn't like obligations and he is the personification of crisp-cold-winter weather. Even if he is friendly, he can be quite dangerous, simply because if you insult him then he would cover you with snow or even worse, he would frost you. He is also known for being a mischief making, carefree and happy spirit, that does as he pleases. Aside the winter part, he is also known as the one that colors the autumn leafs red, yellow, brown and orange, those times he is pictured with a bucket of colors and a paint brush, but tradition of the belief in him is that he leaves frosty-artsy patterns on windows in cold winter mornings.
There are more versions of Jack Frost, one is that he is friendly but kills
if provoked, the other is a much more friendly spirit whose only point is to
enjoy himself and bring happiness to others.
Another thing is that he can be portrayed in various models: as an older man while on the other side he is also shown as a teenager or a young adult.