how long?

One night.

While I have come across little scientific data to verify the consensus, generally people believe that it will not begin to deteriorate for at least a year or once it is less than half full. I've personally not noticed obvious deterioration, but I try to rotate my collection so that there are only a few open bottles at any one time. This allows me to get to know those whiskies better (than if tons are open), and avoids the possibility of them going south...if they should be inclined to do so. Of course, they should always be sealed as much as possible and stored away from light, not too hot or cold, et cetera.

How sensitive is whisky to heat? It is a hot summer and I don't have the air conditioning running while nobody is home during the day.

Also, if I come home to have a dram would the whisky be above its optimal temperature if it has been a hot day? What is the best approach to solving that?

Thanks.

You don't live in a tin warehouse, I hope? Seriously, I would venture that it will be okay. Others may disagree, but it's not like wine. The wine scare is true, but I haven't had great problems with my malts. In fact, in my last place my "cabinet" was a large shelf in the laundry closet which was always warming up quite nicely, and this did not cause problems. Above 100 F is probably not a good idea.

Well, if you drink several in a row, it might not matter :-S

Personally, I don't mind a warm dram--not ideal, but fine. Too cold and I'm really bothered because it masks the taste. Same with espresso, but reversed. Cheese, OTOH, I'm VERY particular about regarding temperature. The main thing is that if you notice a decline in the taste, or the texture caused by the elevated temperature causes you to have a less than perfect, then, you will probably want to correct it.

If you need to chill a single dram, you might simply put it in the refrigerator for a while. (Heresy, yes, I know!) Now, if I were to do this, I would go to great lengths by covering my glass with plastic wrap, but, then, I'm ridiculously tedious. And I don't need to 'cause I'm find with a warm dram. Others here are more particular, and in some cases legitimately.

John