Question

why do tire inflation alarms read high pressure in the summer and low pressure in the winter?

Explanation:

This phenomenon is explained by the ideal gas law ($PV = nRT$), where $P$ is pressure, $V$ is volume, $n$ is the amount of gas, $R$ is the gas constant, and $T$ is temperature (in Kelvin). For a tire, the volume ($V$) and the amount of gas ($n$) are approximately constant (assuming no leaks and negligible volume change of the tire). In summer, the temperature ($T$) is higher. From the ideal gas law, when $V$ and $n$ are constant, pressure ($P$) is directly proportional to temperature ($T$) ($P\propto T$). So higher temperature leads to higher pressure, causing the alarm to read high. In winter, the temperature ($T$) is lower, so the pressure ($P$) decreases, leading to the alarm reading low.

Answer:

This is due to the ideal gas law ($PV = nRT$). For a tire (constant $V$, $n$), pressure ($P$) is directly proportional to temperature ($T$). Summer's higher $T$ increases $P$ (high - pressure alarm), winter's lower $T$ decreases $P$ (low - pressure alarm).