May I ask why the cameras are pretty clear during the day but so grainy at night?

[ENJKL]

I am happy with the daytime footage I receive on my phone app but during the evening, the footage is so grainy that I can't make out too much. I have them facing the front sidewalk and if anything did happen and I needed to refer to the footage, it would be hard-pressed to see details. 

[JamesC]

Poor lighting could result in a less detailed image. It's difficult to make a suggestion without more details/information about your environment. I encourage you to post screenshots here on the community in the appropriate board for your camera model or reach out to support within the Arlo mobile app under Settings > Support to further investigate the issue.

JamesC