No and maybe.

DryFire works best in subdued light. This is because the pulse of invisible light fired from your gun barrel is in the infra-red part of the spectrum. Direct sunlight also contains infra-red so it is best to ensure that sunlight is not directly falling onto the wall you are using for target projection.
In most cases DryFire will work perfectly well during normal daylight though you may have to close the curtains (drapes, blinds) slightly to avoid direct sunlight.

DryFire has an auto-exposure function and will tell you if there are stray sources of bright light in the room.