Lapse rate converter
Convert how fast temperature changes with height or depth: K/km, °C/100 m, °C/1000 ft, °F/1000 ft and K/m.
That's about the same as the standard atmosphere. Climbing the 3,800 m from Chamonix to the top of Mont Blanc, that is 24.7 °C colder.
What it means
How fast does it cool?
Real lapse rates change with humidity, time of day and weather; inversions make them negative.
Every unit
Your lapse rate in every unit
Learn
Three things worth knowing
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2 °C per 1,000 ft
The standard atmosphere’s 6.5 K/km is 1.98 °C or 3.57 °F per 1,000 ft.
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Why rising air cools
Pressure falls with height, so a rising parcel of air expands and spends energy pushing outward. With no heat coming in, it cools: 9.8 K per km when dry.
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°F per 1,000 ft is not °C
A lapse of 2 per 1,000 ft is the standard rate only in °C; in °F the standard is 3.57.
Shortcuts
Popular lapse rate conversions
Background
About lapse rates
Climb a mountain and the air cools: about 6.5 °C per kilometer in the standard atmosphere, or roughly 2 °C per 1,000 feet as pilots learn it. Dry air cools faster, 9.8 °C/km; cloudy, saturated air slower, about 5.
Go down a mine and the opposite happens: the rock warms about 25 °C per kilometer, the geothermal gradient.