I have Raynaud's disease and cold weather alone isn't a trigger for me unless I am not wearing gloves and if I am holding onto something. A shovel when shovelling snow, or pulling a heavy cart. It has to be a continuous session not just one thing for a few minutes.

I've also been sitting quietly at home and suddenly half my thumb goes purple and the other half is fine.

You know it's Raynaud's syndrome because it feels like someone hit your hand with a hammer. It's not just cold hands it's the pain too.

Thanks for the link! I had not heard of the syndrome before. but it could be what my wife has been suffering from for the past year or two. We already are waiting to see a specialist to have a look at her, so I won't make any conclusions, but that seems very likely it.