Why does cold weather dry my skin out? Generally things dry out more slowly the colder it is, yet as soon as winter arrives my hands become so dry the skin splits.

In Russia it is very visible that colds and flus are most widespread in autumn, secondly in spring and when it gets warmer than usual in winter. Let's say, about plus ten to minus two. Hardly anyone gets a cold at minus twenty. People explain it by saying that the viruses can't survive in very cold air, but I find this doubtful because almost all human interaction takes place indoors at those times.

What explanations I could imagine to be right:

1) the viruses can't survive in very dry air. It is well konwn that very cold air gets very dry as soon as you heat it (breathe it in or let it into the house).

2) the cold itself doesn't strain the immune system but rather strengthens it - it's the change that is hard to bear, especially the change from summer (one temperature everywhere) to autumn (big difference between indoors and outdoors). That would also explain why you often get a cold in summer when you spend time in an air-conditioned house or car, not being used to it.

3) Our grandmothers were right after all - the worst thing is getting wet feet...

When I start to get a cold, I feel generally quite ill for the first 24-36 hours, then feel ok again, aside from the specific cold symptoms.  I have always assumed that this turning point represented the point at which your immune system kicked in and started dealing with the virus.  But if this is the case, how come colds take such a long time to clear up?  Why do we go through a succession of symptoms (nose, throat, chest) -  if your immune system can recognise and deal with the virus when it's making your nose run, why doesn't it stop the progression to your throat and chest or at least deal with it a lot faster?  And, at what point do you stop being infectious?

I have heard that the very cold temperatures we are experiecing can cause diesel to freeze. I heard that the temperature is around -12 degrees, is this true?

I have thought of this question as this can effect everybody.

We keep foodstuffs in the fridge to reduce bacterial spoilage but are there any bacteria that thrive best at fridge temperatures? Are some foodstuffs more likely to spoil in the fridge rather than out of it because they carry such bacteria?

Peter Hunt, Teignmouth, Devon, UK

If I put my hand in very hot water, sometimes my skin gets confused and it feels as though I've dipped my hand in cold water.

Why does this happen, and at/after what temperature does this occur?

I've just read your excellent book and have enjoyed it thoroughly

However the answer to the title question left me wondering a little as to be honest the answers given were more of a "why doesn't a Penguin lose too much heat through it's feet."

I've worked in a frozen food vendor and I know that on Mondays when the freezers were right down to temperature of near -30 I would stick to surfaces if I was daft enough to touch them (it had to be tried - not that I'm recommending it!).

I know really cold snow is powdery, but still that layer of cells in contact must be -30 or so on one side and above freezing on the other. Why are they not killed ?

Many animals have dead cells "fur etc." in contact, but not Penguins as far as I know

So if it's OK can I ask it again please

Regards

Andy