If you look at the documentation link on the last (download) step (assuming you have downloaded the data using my other KZbin video), it tells you what the various codes mean. For example, for Visibility the values are in Miles

+Adnane Labbaci If you look at the documentation link on the last (download) step (assuming you have downloaded the data using my other KZbin video), it tells you what the various codes mean. For example, for precipitation: E = 1 report of 12-hour precipitation amount. F = Summation of 2 reports of 12-hour precipitation amount. make sure you look at this documentation in order to understand the variables in the file and what the various codes mean.