Description / Abstract:
"Hot Day", "Tropical Day", "Standard Day", "Polar Day", and
"Cold Day" are part of the lexicon of the aircraft industry. These
terms are generally understood to refer to specific, generally
accepted characteristics of atmospheric temperature versus pressure
altitude. There are also other, less well-known days, defined by
their frequency of occurrence, such as "1% Hot Day", "10% Cold
Day", or "Highest Recorded Day". These temperature characteristics
have their origins in multiple sources, including U.S. military
specifications which are no longer in force.
Purpose
This document is intended to preserve the commonly used day
types in an accessible form for future use, make recommendations
for their consistent usage, and collect the data in a single
format.