Kids Columbia coats and warmth?

[wendibird22]

Anyone know how to judge temperature ratings for kids Columbia coats? I tried online chat with a CS agent at one site and they had absolutely no clue and the Columbia site isn't helpful either. They do list the weight of the insulation...like 60gm or 150gm, but I"m not sure what that correlates to. Obviously the higher number is warmer but are we talking warm enough for Antarctica? I'm looking for an every day winter coat for DD1 that I can add snow bibs to for outdoor play.

[HIU8]

DS has their 3 in 1 version. He says it's really warm. He wears the fleece during the fall and with the shell for the winter. This is the coat that he wore all winter last year with this snow bibs (and he stays outside for a very long time). I have no idea about the temperature rating (last year I looked for that info but never found it). I'm just going by DS who says the coat is really warm.