Port of Brooke Anderson and Roger Peng's weathermetrics package to Lua.
You can find their original work at this URL:
http://cran.r-project.org/web/packages/weathermetrics/index.html
From their package:
Description: weathermetrics includes functions to calculate dew point temperature, relative humidity, and heat index and to convert between Celsius and Fahrenheit. All functions are based on equations and algorithms used by the United States National Weather Service.
This port to Lua employs the same MIT license as the original work.