It is not normal to have cold hands all day even if it's hot but there are factors that contribute to the condition. It could be there is bad blood circulation in the body, you could be having Raynaud's syndrome or you have a genetic hereditary illness known as Raynard's disease. The best thing to don't is to see a doctor for specialized treatment and advice.
The most common reason for cold hands is hypothyroidism (underactive thyroid). You should be checked out by a doctor, but there is no need to panic thinking that you have a life-threatening condition. If you have your thyroid checked, make sure that they check your T3 and T4 levels. You may find the following link informational: www.thyroid-weight-loss.com The information which you may find most useful appears on page 5.
My Mother and I are like that as well it is caused by a lack of iron produced in your body which is called anemia and you can get checked for it by your local doctor and they can proscribe medicine to help it go away