The message .com
from "jaycee" contains these words:


crb wrote:
Andrew Gabriel wrote:
No, I get believable readings from clouds, typically -40 to -50,
which agrees with what aircraft report as the outside temperature.


Clouds at -40 to -50? - I don't think so. You have to go to around
30,000 feet or above to get down to those temperatures.

CRB

Sea level standard is ISA 15 deg. C and a lapse rate of 1. 98 deg. per
1000' you can work it out for yourself? Although in different parts of
the world the altitude temp does not always follow the formulae.

The adiabatic temperature drop I remember from my school days more than
40 years ago was 3 degrees per thousand feet.

A quick google led me to Wikipedia (I wonder why:-)) and an article that
purported to explain the differences between Environmental lapse rate
(1.99 degrees C/1000 ft), Dry adiabatic lapse rate (3/1000) and Moist
adiabatic lapse rate (1.51/1000).

ISTM that on the basis of that article 3 degrees per thousand feet
should be the figure to use to determine the temperature drop between
ground and cloud.

--
Roger Chapman