[muawiyah]

Sounds like you have a problem inherited from your ancient, distant Northern Scandinavian or Siberian ancestors.

When cold weather arrives your veins sink into your meat.

Just use the back of your hand, maybe both if they want more than two vials of blood.

[Myrddin]

It's winter and my hands were cold. That definitely makes the veins disappear. They did use the back of my right hand with a small butterfly needle for the IV last week. When it's warm, I don't generally have a problem.

Having lived in San Diego and Pocatello, I'm definitely better suited to a cold climate. As long as I'm wearing a medium long sleeve shirt, I'm good down to around +34 without a jacket. I can tolerate riding my motorcycle around in +26F as long as the streets have no ice patches. The summer weather here is bone dry. I handle that just fine. Add a little humidity and I'm soaked to the skin with perspiration.