METEOX Meteox is a free site, ideal for flight planning. Shows a radar service for UK and Europe
XCWEATHER XCWeather is free weather service for the UK and Europe.
THE MET OFFICE The free service includes F214, F215, Metars/Tafs. Requires registration.
SAT24.COM A free weather service with a UK Vis Satellite with many other features.
UK SURFACE PLOT Free weather service covering the UK, Europe and other countries
AV BRIEF This site offers some free services available via registration
AVIATION WEATHER MAPS/FLYING IN EUROPE Another free and comprehensive flight. Includes Europe.
ACCUWEATHER A free service offering up to the minute weather
SKY DEMON LIGHT This site shows a graphical NOTAM display within UK air space.
VENTUSKY A free site focusing on weather prediction and meteorological data visualisation
JEPPESEN Online European light weather
OLIVIA The "On Line Integrated tool for Visualization of Information for Airmen"