If you check out the NHRA website, they post altitude correction factors for each registered drag strip. Presumably if the strip you run on isn't on the list, it's at a low enough elevation not to need correction, or it's an on ramp.
Anyway, if you run in Denver or Albuquerque, you need to consider these things, as it's terribly depressing to try hard just to break 15! I ran a 15.08 yesterday, faster than the other Minis by a full second, but once corrected for altitude it's 14.5 (using the half stock class correction factor-half because the car is forced induction.) Even the speed has a correction factor--96mph turns into nearly 100 after correction.

One of the great things about dragging is that is holds many factors constant to allow comparisons of cars. The comparison on the same track, same day is almost perfect, but using correction factors allows for some comparisons across place and time.

 

My uncle races a 68 camaro with with a 468, Last weekend here in denver he ran a 10.528 at 121MPH, all i know is when he goes to the lower altitude the car runs low 9's. so from sea level to the mile high city you either lose or gain a little over a full second. just my thoughts and what ive learned on the topic

 

Tommy: You don't need experience with this one--it's physics. Pure and simple. My point is that people don't correct their 1/4 mile times when posting, yet they only post elevation-corrected (and SAE corrected) dyno numbers. My 15sec 1/4 mile here in Albuquerque is a helluva lot faster time than it seems when compared to a sea level 15 second run.
As you live in Denver, you know what it's like to live and breath with 15% less oxygen in each breath. Our Minis also know what that feels like.

 

No, your 15 sec run at altitude is just as slow as a 15 sec run @ sea level. the launch, acceleration, and shifting were all at the same rate.

Obviously at sea level your car will be much more powerful, and probably faster, but also have more slip. You would have to react to all this and drive faster too, which you can probably do. You might end up needing an extra shift if your car goes faster.

My point is there are too many variables other than oxygen to correct a high altitude run into a certain sea level run that you and your car would have performed.