How does temperature variation affect the altimeter?

The correct understanding of how temperature variation affects the altimeter is based on the principles of atmospheric pressure and temperature. As temperature increases, the air becomes less dense. This change in density leads to variations in atmospheric pressure levels.

When the air is warmer, it expands, causing the pressure levels to rise. An altimeter calculates altitude based on the current atmospheric pressure compared to a standard setting. Therefore, if the air temperature is warmer, and the pressure levels are higher, the altimeter will indicate a lower altitude than you are actually at. This is because the altimeter is calibrated to expect a standard rate of pressure change with altitude, which does not account for the effects of higher temperatures.

Thus, on warm days, the altimeter may suggest that you are at a lower altitude, which emphasizes the necessity for pilots to adjust their understanding and practice in relation to the ambient temperature and its impact on their altimeter readings during flight operations. This understanding is crucial for accurate navigation and safety.