Ace's Pilot Shop Weather Data
   Aviation weather and flight planning, including forecasts, observations, weather maps, DUATS briefings, icing, and turbulence.
   http://www.acespilotshop.com/wx2.htm

Aviation Weather
   Displays live pilot reports, current and forecasted weather (PIREPs, METARs, TAFs), temporary flight restrictions (TFRs) with optional radar overlays using Google maps.
   http://maps.avnwx.com

Aviation Weather Center
   The National Weather Service's aviation weather site with official forecast products as well as experimental products.
   http://aviationweather.noaa.gov/

BalloonCast
   Customized weather for balloon pilots. METARs, TAFs, winds aloft, sunrise/set for multiple stations compared side by side, all codes translated to English and times converted to local.
   http://www.blastvalve.com/weather/

Base Ops
   Aviation Weather for Flight Preparation with TAF Metar Sigmet Radar and Sat-pictures.
   http://www.baseops.de/

Data Transformation Corp DUAT
   FAA's Direct User Access Terminal service provides free aviation weather and flight planning for certified pilots in the US.
   http://www.duat.com

Enflight
   Obtain plain-language weather briefings using exclusive WXpert translation. View up-to-date weather graphics. Helps prepare and file flight plans. Available both on the Web and on mobile PDAs (Palm i705, etc.)
   http://www.enflight.com/

Flying in Europe
   Weather information for flying in Europe, including all airport notams, calculations, country information, airport webcams, FBO database, and all aviation abbreviations.
   http://www.flyingineurope.be

Northwest Airlines Meteorology
   Providing weather forecasting products for the aviation industry, including specialized turbulence and thunderstorm forecasts.
   http://www.nwa.com/weather

Pilot Weather Briefing
   Free weather information for pilots, including surface conditions, upper level winds, turbulence, icing, thunderstorms, TAFs and Metars, radar and satellite images.
   http://www.pilotweatherbriefing.com

Pilot's Guide to Aviation Weather Services
   An online brochure to help pilots use the "National Aviation Weather System."
   http://www.nws.noaa.gov/om/brochures/pilot.htm

SA Weather Service - Aviation
   Provides weather services for the aviation industry in Southern Africa. Includes metars, sigmet charts and forecasts.
   http://aviation.weathersa.co.za

Turbulence Forecast
   Turbulence forecast maps for around the world.
   http://www.turbulenceforecast.com

Upper Midwest Aviation Weather
   Central reference for aviation weather resources, focusing on current and forecast conditions in the upper midwest region of the US, including Minnesota, Wisconsin, South Dakota, North Dakota, and Iowa.
   http://weather.cloud7.org/

WSI
   Provides pre-flight and in-flight weather information. Aviation weather also available online through WSI Pilotbrief.
   http://www.wsi.com/solutions/aviation/

Winds and Temperatures Aloft
   By selecting one of over 160 continental cities in the U.S.A. or one of 30 cities in Alaska, you can obtain wind direction, speed, and temperature forecasts.
   http://www.usairnet.com/cgi-bin/Winds/Aloft.cgi