Each forecast (PWG, PWE, GFS & ECMWF) is updated twice a day, every 12 hours.
You can see the update times for your GMT time zone at http://support.predictwind.com/hc/en-us/sections/200085734-Forecast-Update-Times
The next forecast update time is displayed in the PredictWind Website and PredictWind App. Details can be viewed in real time, and are written below the forecast location name.