# Freezing level equation

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ok, I have an equation to determine the freezing level using surface temp, but it's for Farenheit.

I can't find one for Celcius and I am annoyed by having to convert C to F. Was hoping there was one for C, or maybe someone is smarter than I and can figure it out for me!

Here's the Farenheit equation:

Surface temp (F) - 32, divided by 3.2 = freezing level (need to move decimal over x3 MSL)

50 - 32 / 3.2 = 5.6 or 5600'

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The standard lapse rate is 2 degrees celsius per 100 feet. Since 50 fahrenheit equals 10 celsius, divide 10 by 2, and multiply that by 1000. Answer comes to 5000 feet. Is that what you're after?

Keep in mind that there are a lot of variables, and that 2 degrees celsius per 1000 feet is only an average. You can, of course, have a temperature inversion where the temperature actually increases with altitude.

Edited by heli.pilot
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I converted your formula to Celsius.

FL = (1000 * (Tf-32)) / 3.2

FL = Tc * 562.5

In your example of 50 deg F:

FL = (1000 * (50-32)) / 3.2

FL = 18000 / 3.2

FL = 5625 or 5,600 feet

50 deg F = 10 deg C. [(50-32) * 5/9]

Therefore, using substitution:

FL = Tc * 562.5

FL = 10 * 562.5

FL = 5625 or 5,600 feet.

The 5-6-2-5 being in common between the two is purely coincidence.

~Jeff

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So couldn't you use temp (10c) divided by 2 (lapse rate) times 1000 plus field elevation

((10/2)*1000)+2643 = 7643 for Tucson.

Jerry

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Standard Lapse Rate = 2 degrees Celcius/1000'

Saturated Lapse Rate = 1.5 degrees Celcius/1000'

So if it's 7C on the ground and an overcast layer at 2000' AGL, your freezing level will be around 4000' AGL. Thankfull my base is about 20' ASL to it makes for very easy math. ## Join the conversation

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