What air pressure condition causes air to be drawn into the cave?

Air is drawn into a cave primarily due to low air pressure conditions outside compared to the higher air pressure within the cave. When the atmospheric pressure outside decreases, it creates a pressure differential that allows air to flow into the cave's entrance to equalize the pressure. This process can be linked to temperature changes, specific weather conditions, or even the physical geography of the area.

High air pressure, in contrast, would push air out of the cave, counteracting this inflow. Stable air pressure implies that there is no significant difference in pressure to cause any movement, while variable air pressure indicates fluctuations that might not consistently support a drawing effect into the cave. Therefore, low air pressure outside the cave is the crucial factor that leads to the influx of air into the cave system.