The Solunar Theory suggest that the position of the sun and the moon influence the dates and time of day that animals feed. The idea being that there are both major and minor feeding periods.
When it comes to deer hunting, there is often an increase in deer activity during new moon phases. If the Solunar times happen to occur within an hour or two of sunrise or sunset periods, There can also be an increase in deer movement.
There will be other factors involved when it comes to adequate predictions. For one, hunting pressure can reduce the deer activity during daylight hours.
The weather can also be a factor. Changing conditions will certainly have an impact. The rutting period can also play a part as deer become less predictable.
The below Solunar Chart should be used as a suggestion tool. As a hunter, any information can be helpful. For best practices, use this chart along with the moon phase chart but make hunting decisions based on good scouting and knowledge of the deer in your area.