I have constantly annoyed my friends by my inability to stay awake beyond 9 pm on most days. Of course, the upside of this has been my ability to wake up at 4 am, often when most people come home after a hard long night of fun and frolic. People have different circadian rhythms and you really are predisposed to staying awake at night or rising in the morning. So how does this impact your ability to exercise and your preferences of when you do.
If you are like me and prefer to exercise in the morning, the temperature of your body is the lowest. Since a higher core temperature is better for your muscles to work out you need to warm up adequately before you actually start to work out. Your body is stiff and more likely to sustain injuries. However, surprisingly research has shown that your tolerance for pain is higher in the morning and therefore probably your ability to stretch yourself is higher. If you exercise mid morning, you are likely to demonstrate more flexibility and agility. This is because you have likely eaten carbohydrates for breakfast and the body uses this sugar for its energy requirement. If you work out in the evening, your core body temperature is highest and therefore your muscles are best positioned to benefit from the exercise. This gives you the ability to perform high intensity and strenuous exercises and extend the period of your work out longer than you would otherwise. Your hand eye coordination and overall responsiveness is also higher in the evening.
Most importantly, experts suggest to exercise at the same time everyday because apparently your body trains itself to respond to the exercise stimulus and develops the capacity to best benefit from the work out at the same time each day. Working out to close to your bed time has been shown to create elevated hormones that make it hard for you to go to sleep. You understand your body best and the choices you make should be a function of what you are comfortable doing. If dancing away at 2 am is your thing, it beats the hell out of doing nothing at all, so fire away on all cylinders.