I forgot wine in the trunk of my car for a week and the temperature's been pretty hot. Is it okay?
It may not be gone, but it's probably down for the count.
You've no doubt heard of the greenhouse effect. Solar heat enters and can't escape. Your car's trunk, though windowless, is not a pleasant place in summer, and this is July. That's especially true for dark-painted cars, which absorb more radiation than lighter-coloured cars.
I suspect that if the temperature's been very hot where you are, you'll notice the evidence. Heat causes liquid to expand, and this could force the cork upward and beyond the tip of the neck, creating a bulge in the capsule at the top of the bottle. You may also notice sticky residue on the sides of the glass below the capsule. That's wine that has expanded up between the cork, out and down the inside of the capsule. Not a good sign.
After a mere week, your wine will likely still be drinkable and even pleasant, but I suspect it won't be comparable in freshness to the wine you purchased all those days ago. It may taste less fruity and possibly cooked or pruney. Most critically, perhaps, the wine won't age as well. If some liquid did in fact seep out of the bottle, there will be a larger pocket of air below the cork, and that will prematurely oxidize the wine in the months and years ahead. If we're talking wine sealed under a screwcap and that cap is still in good condition, you may be fine.