The answer to how long you can leave ham outside of the refrigerator will depend on several factors, one of the most important of which is temperature. If the ham’s temperature is reasonably cool, it should be okay for several hours. It’s best to make sure that the ham is covered similarly to how it would be in a Lunchable pack if it is left outside of the fridge. But it’s no guarantee. Even ham inside a sealed pack can begin to host bacteria. One thing is for sure, and that is that any ham left outside in warm conditions will only be good for approximately two hours, after which you should throw it into the rubbish bin.