Bergfex – gives good hourly mountain weather prognoses for Switzerland, Austria, Germany, Italy and Slovenia.
MeteoSwiss – this site provides detailed forecasts for the whole of Switzerland. The precipitation radar provides minute-by-minute information about rainfall – a very useful tool.
Yr.no – this Norwegian weather site will work well for locations all over the world. It has hourly information. This site works well if you want a quick general overview of the weather for the next day for a specific location.
Mountain-forecast.com – useful site with very detailed information
Windy.com – a very detailed website by a Czech company. It also has an app you can install on your phone.