Based solely on gameplay, it seems as though there is some "trigger" (not like a script-trigger) that tells AI when they need to use NV goggles. Any idea how that is accomplished? Or get the current ambient lighting parameters? I believe the notoriously circumspect DM is interested in figuring out how near to sunrise and sunset it is, when those times can vary by a couple hours depending on the season.
I have found the lightIsOn query, but that kind of binary result is pretty heavy-handed.