Met Office UK's Met Office, includes aviation-oriented self-briefing data.
WeatherJack Excellent links to useful met websites, as well as a reliable soaring forecast in the summer.
SkyLink Current and forecast weather for Sywell Aerodrome.
MeteoNet Reliable Synoptic Prognosis for next 5 days.
XC Weather Good visualization of UK TAF and METAR data.
MeteoBlue Good variety of forecasting information.
WindGURU Pictogram forecast for Pitsford area designed for windsurfers (ignore the rating- 40kts is bad for microlighting!).