Hellobee Boards

I think it totally depends on the temperature! Remember that they will be climbing back up the hill and probably going to be getting hot too. I would be hesitant to layer too much under the snow pants!

In addition, make sure you have great ski socks and a solid lined hat. That is where you lose a lot of heat if you don't spring for quality.

It all depends on the temperature. For skiing it's easy to get cold but if you're snowboarding it is much more work and you'll get warm quickly! Just make sure you have all skin covered even if it's not a thick layer. I do a fleece gaitor and earband on my head and I wear a top with thumb holes so there's no wrist skin exposed between the gloves and jacket. For sledding if you're walking up the hill you'll get warm quickly!

We dress my 4 year old for skiing like this:

Base layer
Fleece layer
Bib/jacket
Waterproof mittens
Wool socks
Balaclava (if really cold)
Goggles
Helmet (or hat if you're not using one)