Python-metar is a python package for interpreting METAR and SPECI coded weather reports.

METAR and SPECI are coded aviation weather reports. The official coding schemes are specified in the World Meteorological Organization (WMO) Manual on Codes, vol I.1, Part A (WMO-306 I.i.A). US conventions for METAR/SPECI reports vary in a number of ways from the international standard, and are described in chapter 12 of the Federal Meteorological Handbook No.1. (FMH-1 1995), issued by the National Oceanic and Atmospheric Administration (NOAA). General information about the use and history of the METAR standard can be found at

http://www.ncdc.noaa.gov/oa/wdc/metar/

This module extracts the data recorded in the main-body groups of reports that follow the WMO spec or the US conventions, except for the runway state and trend groups, which are parsed but ignored. The most useful remark groups defined in the US spec are parsed, as well, such as the cumulative precipitation, min/max temperature, peak wind and sea-level pressure groups. No other regional conventions are formally supported, but a large number of variant formats found in international reports are accepted.

Current and historical METAR data can be obtained from various places. The current METAR report for a given airport is available at the URL

http://weather.noaa.gov/pub/data/observations/metar/stations/<station>.TXT

where is the four-letter ICAO airport station code. The accompanying script get_report.py will download and decode the current report for any specified station.

The METAR reports for all stations (worldwide) for any "cycle" (i.e., hour) in the last 24 hours are available in a single file at the URL

http://weather.noaa.gov/pub/data/observations/metar/cycles/Z.TXT

where is a 2-digit cycle number (e.g., "00", "05" or "23").

The Federal Meteorological Handbook No.1. (FMH-1 1995), which describes the U.S. standards, is available online at

http://www.ofcm.gov/fmh-1/fmh1.htm

The World Meteorological Organization (WMO) Manual on Codes, vol I.1, Part A (WMO-306 I.i.A) can be downloaded from site I use to distribute this package,

http://homepage.mac.com/wtpollard/Software/FileSharing4.html.

Tom Pollard pollard@alum.mit.edu May 2, 2009

If you're using the anaconda python distribution, you can create a new enviroment with the following:

conda create --name metar33 python=3.3 matplotlib pandas six pip nose ipython-notebook openpyxl

Then clone this repository, activate the recently created environment, and install via pip:

git clone https://github.com/phobson/python-metar.git
cd python-metar
source activate metar33 # omit `source` on Windows

The standard pip command to install would be:

pip install .

However, if you're gonna modify the source code (for whatever reason), pass in the -e flag. That way, you can just restart your python interpreter after altering the source to test your changes.

pip install -e .

There's a small, annoyingly slow test suite that can be run by saying

nosetests --verbose

There are a couple of sample scripts and IPython Notebook, described briefly below.

There's no real documentation to speak of, yet, but feel free to contact me with any questions you might have about how to use this package.

You can always obtain the most recent version of this package using git, via

git clone git://github.com/tomp/python-metar.git

This is a public copy of the code repository I use for development. Thanks to Toby White for making me aware of github.

README  ............. this file

parse_metar.py  ..... a simple commandline driver for the METAR parser

get_report.py ....... a script to download and decode the current reports
                      for one or more stations.

sample.py  .......... a simple script showing how the decoded data
                      can be accessed. (see metar/*.py sources and the
                      test/test_*.py scripts for more examples.)

sample.metar  ....... a sample METAR report (longer than most).  Try
                      feeding this to the parse_metar.py script...
metar/
    Metar.py  ....... the implementation of the Metar class.  This class
                      parses and represents a single METAR report.

    Datatypes.py  ... a support module that defines classes representing
                      different types of meteorological data, including
                      temperature, pressure, speed, distance, direction
                      and position.
test/
    all_tests.py  ... a master test driver, which invokes all of the unit tests

    test_*.py  ...... individual test modules

setup.py  ........... installation script

See the sample.py script for an annonated demonstration of the use of this code. Just as an appetizer, here's an interactive example...

from metar import Metar
obs = Metar.Metar('METAR KEWR 111851Z VRB03G19KT 2SM R04R/3000VP6000FT TSRA BR FEW015 BKN040CB BKN065 OVC200 22/22 A2987 RMK AO2 PK WND 29028/1817 WSHFT 1812 TSB05RAB22 SLP114 FRQ LTGICCCCG TS OHD AND NW -N-E MOV NE P0013 T02270215')
print obs.string()

station: KEWR
type: routine report, cycle 19 (automatic report)
time: Tue Jan 11 18:51:00 2005
temperature: 22.7 C
dew point: 21.5 C
wind: variable at 3 knots, gusting to 19 knots
peak wind: WNW at 28 knots
visibility: 2 miles
visual range: runway 04R: 3000 meters to greater than 6000 meters feet
pressure: 1011.5 mb
weather: thunderstorm with rain; mist
sky: a few clouds at 1500 feet
     broken cumulonimbus at 4000 feet
     broken clouds at 6500 feet
     overcast at 20000 feet
sea-level pressure: 1011.4 mb
1-hour precipitation: 0.13in
remarks:
- Automated station (type 2)
- peak wind 28kt from 290 degrees at 18:17
- wind shift at 18:12
- frequent lightning (intracloud,cloud-to-cloud,cloud-to-ground)
- thunderstorm overhead and NW
- TSB05RAB22 -N-E MOV NE
METAR: METAR KEWR 111851Z VRB03G19KT 2SM R04R/3000VP6000FT TSRA BR FEW015 BKN040CB BKN065 OVC200 22/22 A2987 RMK AO2 PK WND 29028/1817 WSHFT 1812 TSB05RAB22 SLP114 FRQ LTGICCCCG TS OHD AND NW -N-E MOV NE P0013 T02270215

The metar library is

Copyright (c) 2004-2009, Tom Pollard All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.