You might find the following links interesting:
9NEWS.com | Colorado's Online News Leader | Berthoud Pass reopens, Loveland Pass expected closed through Sunday
Stanley, Jan 6 - Colorado Avalanche Information Center
The later might give you pause, but note in closing they say previous to this any vehicle 'caught' was in 1988. As in not common.
The odds are you will be fine, if with proper vehicle and driving safely. There may or may not be snow on the road, but certainly possible given the elevation of Berthoud Pass (11,307 feet). Less chance of encountering inclement weather in December than January. But as the referenced articles point out, this pass and sections of I-70 are liable for closure at any given moment in winter. But I-70 and US 40 are both major arteries, so well maintained, they do their best to keep them open, and they generally are.