Snow or no snow?
The whole snow / no snow thing is probably incapable of resolution. We all know that in hilly areas - especially those high above sea level - the climate can be pretty local. Also, if snow has already fallen some days before, patches can linger on hill sides and in crevices where the sunlight cannot reach. I'm often up in the Peak District near Buxton and Bakewell and I've seen that happen many times.
Having said that, if you look at the other famous German newsreel clips from around the same time it's clear that it wasn't snowing during the early stages of the advance and it's hard to see much evidence of recent snowfall. Even where it might be visible, it is impossible to accurately verify the timing and location.
The images from Poteau don't show any snow and the footage below (which actually made it back to Germany and was shown in a newsreel at the time) also shows no signs of the white stuff. They include the well-known sequence of Kamfgruppe Peiper advancing into Stoumont - an attack which began during the morning of the 19th.
But, then again, look at this rather grim image taken in Honsfeld (on the way to Malmedy and the sight of the infamous massacre), which shows elements of Fallschirmjäger-Regiment 9 stripping boots from the bodies of killed GIs. Honsfield was captured on the morning of the 17th December, with Malmedy being overrun later the same day.
For obvious reasons these images did not make it into the German cinemas at the time. Not only do they suggest that these Americans had been summarily executed - they also show the rather parlous state of the attacker's equipment at an early stage of the campaign.
For obvious reasons this shot must have been taken soon after the battle and, as we can see, there are clumps of snow at the side of the road, on the outbuilding in the background (but not the main roofs of the houses) and, it seems, over the fields in the distance.
Honsfield is about 15 kms northeast of Kaiserbarracke, but it may be further above sea level for all I know. Either way, it seems that there had been recent snow fall in some parts of the area of advance even if the snow would not return in any meaningful way for some days ahead.
So I may allow myself to include some snow after all...