There are very many weather sites on the Internet, and also a huge range of weather Apps for mobile devices. Everyone has their own favourite. Since my previously favourite weather site is no longer any good; these are the one I use:

• The BBC weather page. Accuracy is the main advantage, plus there are forecasts for a reasonable selection of locations.
• accuweather. Probably supports forecasts for a wider selection of locations than any other site. Also available as an App for mobile devices.