Exterior surface fluid relief apparatuses, and associated systems and methods

A drain apparatus comprising:

• an outer ring including:
• a first ring section including a first sloped portion, wherein the first ring section defines an opening through the outer ring;
• a second ring section including a second sloped portion, wherein the second ring section forms a perimeter of the outer ring;
• and
• an outer coupling mechanism configured to clamp the first ring section to the second ring section such that the first and second sloped portions mate;
• and
• an inner plug configured to be positioned in the opening of the outer ring and to be coupled to the outer ring, the inner plug including:
• a first plug section including a first beveled portion;
• a second plug section including a second beveled portion, wherein the second plug section forms a perimeter of the inner plug;
• a film configured to transmit light through the drain apparatus;
• and
• an inner coupling mechanism configured to clamp the first plug section to the second plug section such that the film is clamped between the first and second beveled portions;
• wherein the inner plug is configured to decouple from the outer ring when a threshold weight of fluid is positioned on top of the inner plug.