Temperature lapse rate

Temperature lapse rate is the rate at which atmospheric temperature changes with altitude. A lapse rate describes how many degrees temperature changes over a specified vertical distance. Meteorologists and aviation texts use lapse rates to analyze stability, convection, cloud development, and the standard atmosphere.

How it works

In the standard atmosphere, temperature decreases with altitude through the lower atmosphere at a defined reference rate. The actual environmental lapse rate can be steeper, weaker, or even show temperature increasing with altitude. An inversion is a layer where temperature increases with altitude, which can affect mixing, visibility, and turbulence.

The dry adiabatic lapse rate describes how an unsaturated parcel of air changes temperature as it rises or descends without exchanging heat with its surroundings. It is different from the environmental lapse rate measured in the atmosphere. The two are compared when discussing atmospheric stability.

Example

A weather briefing may show a strong temperature inversion near the surface. A pilot may then expect different visibility, wind, and turbulence behavior than a simple standard atmosphere estimate suggests. A density altitude calculation still uses its stated formula and input assumptions.

Why it matters

Temperature affects air density and aircraft performance. Lapse rate also helps explain cloud bases, convection, turbulence, and temperature changes along a climb. It does not by itself predict all weather conditions, because moisture, terrain, wind, and lifting mechanisms matter too.

Use current weather products and the aircraft's performance information. The NOAA Aviation Weather Center provides weather references, while the POH or AFM controls aircraft-specific performance.

Related terms and tools

• Standard atmosphere
• Density altitude
• Density altitude calculator