Running

I said a few things, not sure which you think is wrong. (By the way, I am totally comfortable with being wrong. Apparently it's the new being right.) My thoughts on this topic have been shaped by Tim Noakes (whose book 'Lore of Running' I have had to buy three times now). Over-hydration is a much bigger threat than dehydration in organised races: I think hyponatria was the cause of death of the last person to die in the London Marathon, for example. Noakes' view is that we should be guided by our thirst about whether we should take on water, niceties about reduced thirst drive to one side. I find it difficult to believe that the folk who rush to the water station at the 4k mark are responding to their thirst.

More on this (in an accessible form):

http://www.runnersworld.com/article/0,7120,s6-242-302--8785-1-3-2,00.html

Google 'Timothy Noakes Hydration' for the medical papers.

The cold weather= no drinking.

Thirst is not a good indication of hydration level. The amount of hormonal influences* on it alone, let alone the fact it deteriorates with age, mental state, and emotional state, means that as a measure of your body's hydration- it is poor at best. It's a truism, but "when you feel thirsty, you're already dehydrated" holds good.

As I said upthread- Over hydration is not the problem (even if you drank Noakes' reccomended amount, you'd still face potential hyponatraemia, because you're body is not replacing the sodium), but incorrect hydration is.

And just as a final point, I'm not saying for a minute that I advocate a certain level of drinking. My knowledge is purely from a non-excercise specific endocrine book, published 2010, so fairly up to date, so I have no amount that I would recommend, however, from your link- the advice at the very end is probably the best:

follow the USA Track & Field guidelines that recommend weighing yourself before and after a workout to determine your unique sweat rate per hour. From this, you can plan how much to drink every 15 to 20 minutes while running a marathon. (Sixteen ounces of fluid for every pound you lose.)

I'd suggest to not trust your thirst, its fallible, and doesn't measure the key variable in this situation, which isn't blood volume, but [Na].
That's what will kill you.

*Best example I can think of at the top of my head- during the menstrual cycle women exhibit different thirst levels, depending on the stage in the cycle.