How long will they last?

[Derek]

Hi
I guess I'm a newbie to a lot of this though have enjoyed wine for a long time. I have a small stock of wines that theoretically will improve with a few years cellaring according to the info I have on them. I don't have a cellar, just a rack in the large understair cupboard which is both dark and the coolest part of the house. In summer though the temp is going to squeeze up past 20 deg C possibly towards 24. I know this is really far from ideal, but it is the best I have (my father has a better room under his house that would be good but not safe as he would drink my wine) [img]http://www.wines.com/ubb2/smile.gif[/img]
Basically I'm not trying to longterm cellar anything but just have some wine that might improve a bit with a little longer in the bottle.
So my question is whether anyone can give me any ideas as to how long I can expect things to last in this kind of enviroment.

Thanks all - Derek