What does it mean to be Light Dominant or Dark Dominant?
If you have lived among humans for any length of time, you are surely familiar with the expressions "early bird" and "night owl".These two expressions describe human sleeping habits and the time of day when they are most productive.
The truth is, the time of our birth determines when our energy, mental skills, awareness, creativity, and just about everything else about us, is at our strongest.
However, sometimes our true dominant self is conditioned to the wrong time of the day/night cycle. This can occur with shift work, school, social events, having a new baby, illness, our partner's dominant cycle, etc.
Because of this conditioning we may think we are dominant in the wrong time of the day/night cycle and not realize we could be even stronger if we were functioning under the right time cycle.

~ If you were born at or
after sunrise and
before sunset, then your are
LIGHT DOMINANT.What this means is that you are at your best during the day hours. You enjoy rising early and getting things done during the day. Whether it is taking a morning jog or spending the sunrise hours in quiet meditation, the sun is your friend. You think better in a well lit environment and your mood is enhanced by the feel of warm sun rays on your face. As the day nears its end so does your energy. You enjoy an early bedtime.

~ If you were born at or
after sunset and
before sunrise, then you are
DARK DOMINANT. If you are a Dark Dominant Sign, you are at your best during the quiet peaceful night. You find the sun's energy overwhelming and
draining, therefore you wait until dusk for meditation and exercise. Your mind is more clear in dark serenity and the night sky improves your mood and creativity. You easily spend hours stargazing and often work well into the night.
Information found at
http://www.freewebs.com/fantasyhoroscopes/dayornight.htm