The question has been raised – why does the practice of ‘ghost hunting’ occur only at night? Here is a list of reasons I have been able to find why this occurs – leaving it open to your interpretation if it is valid or not.
Darkness.
I think that the primary thing people go for is the spook factor – that largely occurs at night. When you can’t see what is going on, the world becomes a much scarier place. When you are relying on a flashlight, or even worse, a night vision camera for sight, the world becomes a lot more hectic. And when there are noises, that you cannot instantly explain, they must be from another world.
The inability to see everything that is going on, instantly causes people to attribute the unexplained to the actions of ghosts. Being alone in the dark leads people to rely on the knowledge that they know – which may delve up into research that has conducted on ‘spirits’ that may have passed there.
However, from experience, I can tell you that people see what they have heard. During one investigation I conducted, I created a ‘fake’ paranormal entity, and gave background research on her. Not surprising, people believed they found evidence that she was trying to communicate with us.
The Witching Hour.
Sadly, the hunt for the Paranormal still has a lot to do with what is perceived as a “Witching Hour” which occurs at 3:13 AM. This is the time when evil spirits are supposed to be in their fullest power.
However, my challenge to this would be that spirits are not inadvertently evil. I guess it fundamentally depends on what you think are grounding them to this world. But, I would think that at least 90% of the alleged haunted entities out there are victims of tragic circumstances, more than anything else.
Moisture in the Air.
There are only two reasons that I think are semi-valid in this argument for the darkness, and moisture in the air tends to be one of them. With the basis that spirits are comprised of energy, it makes sense that when there is more moisture in the air, spirits would have an easier time materializing and making their presence known.
Quiet and Uninterrupted.
This is the second reason I can understand why, later at night might prove to be more effective – because things are quieter and there is less human activity going on. Perhaps, when it is is quieter, ghosts have an easier time being heard because they speak so softly.
Perhaps, when the world is less active, the presence and movement of a ghosts is more easily seen.
Hopefully, this answers more in the question posed, “Do ghosts come out during the day?”.
Another reason to investigate at night – luminous phenomena are more easily spotted in a dark space than in a brightly-lit one. Whether or not it’s accurate, people do seem to presume that when ghosts manifest visibly, it is as some kind of glowing apparition. That this presumption is the case is reflected by the myriad depictions of ghosts in movies – almost always glowing.
I am uncertain whether ghosts actually glow when they do become visible to the eye, though I can think of several reasons why they might. If they do, then spotting them ought to be much easier at night.