This paper presents findings based on the examination of time-series tire pressure data. Tire pressure is important to vehicle safety due to its effects on vehicle handling and stability, as well as the impact that inappropriate tire pressure has on tire wear and tire failures. Previous research such as NHTSA’s 2001 Tire Pressure Special Study sampled vehicle populations and recorded tire pressures at a single point in time. Such studies yield important insights into tire pressures on individual vehicles and across the vehicle populations, but cannot provide insights into the behavior of tire pressures over time.The data presented in this paper was measured using the tire pressure monitoring system (TPMS) data from Tesla Model S vehicles. Using Tesla’s on-board diagnostic data logging and remote data retrieval capabilities, the time history of each vehicle’s tire pressures was recorded and fleet-wide data was analyzed. The resulting analysis provides insights into tire pressure changes caused by permeation and slow leaks as well as temperature fluctuations at both drive-cycle and seasonal time scales. The paper also includes examples of tire punctures with resulting pressure data.