METAR Decoder utility

These are Windows and command-line (AKA console) versions of a utility which will decode a METAR weather-information string. METAR strings are displayed on many online weather pages; while they are typically incomprehensible to humans, they are (relatively) easily parsed by computers. A typical METAR string looks like this:

METAR KLVK 141853Z 30009KT 10SM CLR 28/09 A2996 RMK AO2 SLP140 T02830094

Metar.exe will decode this string and present an output such as this:

*****************************************************
INPUT METAR REPORT:
   METAR KLVK 141853Z 30009KT 10SM CLR 28/09 A2996 RMK AO2 SLP140 T02830094

/*******************************************/
/*    DECODED METAR REPORT
/*******************************************/
REPORT CODE NAME    : METAR
STATION ID          : KLVK: LIVERMORE, CA, loc 37.42N, 121.49W, elev 117 meters
OBSERVATION DATE    : 14th, 1853
WIND DIRECTION      : 300
WIND SPEED          : 9
WIND UNITS          : KT
PREVAIL VSBY (SM)   : 10.000
CLOUD COVER         : CLR
TEMP. (degsF)       : 82
D.P. TEMP. (degsF)  : 48
ALTIMETER (INCHES)  : 29.96
AUTO INDICATOR      : AO2
SLP (hPa)           : 1014.0
TMP2TENTHS (degsF)  : 82.9
DPT2TENTHS (degsF)  : 48.9

WMetar - WinAPI version of this program
WMetar is freeware, source code is available below.

Download WMetar program and data here

Download WMetar source code here

Using the Metar command-line utility
Executing the utility with no arguments will present a usage screen:

> metar
Usage: metar [options] [optional METAR string]
Options:
 -f  show temperatures in Fahrenheit vs Celsus
 -t  run the build-in test vectors

NOTE: settings options *must* precede a METAR string!

So, to get the output shown above, I entered:

metar -f "METAR KLVK 141853Z 30009KT 10SM CLR 28/09 A2996 RMK AO2 SLP140 T02830094"

Note that the METAR string must be enclosed in quotes.

Metar is freeware, source code is available below.

Download Metar utility here

Download Metar source code here

Background on this program

The original METAR Decoder Software Package that this utility is based upon, originally was provided by the National Weather Service, according to Eric McCarthy, who maintains a website devoted to the package, and did some development on it in the early 2000s.

In 2011, he moved the project to SourceForge, where I found the code that I started with. Unfortunately, this code base does not build with Gnu gcc, so I had to do some work on it. Once it was building, I added some features to it, including allowing passing of the METAR string from the command line, and I also added support for the stations.txt file which is maintained by Greg Thompson. This file allows the program to translate the Station ID (KLVK in the above example) into useful location description and information.

Metar is written in standard C, and builds on Windows and Linux. The Windows version is built using the open source MinGW (Minimal Gnu for Windows) tools, and requires a couple of the common utilities from Cygwin as well (Gnu make, rm, etc).