Hi
The first question I was asked by the nurse when Sophie was 2 weeks old was 'is she sleeping outside?'. It was minus 10 at the time. Babies are encouraged to sleep outside here from a very young age, it is good for their immune system and helps them to sleep bette/deeper.
To sleep or go outside when it was very cold (below 10) I used to put her in her normal clothes, add a wool babygro and her snow suit, stick her on a sheepskin and then wrap her inside a sleeping bag with a blanket. She'd also have 2 sets of gloves (wool and then proper gloves) wool socks and booties, and a hat or two!
A make of clothing that we have used (last year and this year) is Reima- they make great snowsuits but can be expensive. They are waterproof and are apparently warm enough for minus 30 (not sure where I read that). You can put a wool layer underneath as well for extra cold days- you can buy these in the supermarket or from a company called Ruskovilla (lovely stuff for winter).
My DD is now is Goretex boots with wool socks and normal socks as she gets very cold feet, for her hands she has wool gloves and then waterproof, insulated Reima gloves. I really recommend a balaclava too as they cover the neck area. The make we have is Kivat. We got ours in the supermarket (CM). If it is extra cold she will wear a little silk hat under the balaclava too
When the snow starts to melt most kids add waterproof/rubber overalls over their snowsuits- the main brand of this is Rukka.
I have a page onhow to dress your baby on my website-
http://www.quayclark.com/sophie12.aspx
No idea on how prices differ between here and Germany. I'd be more inclined to buy from Finland aas the weather is colder here and so clothes are specifically made for Finnish weather. If the weather here continues as it does, it should be tropical in January!
Hannah