Waze boasts a great user-friendly interface. If you're already familiar with the app, look for this new feature by selecting the “Report” icon, then “Hazard,” then “Weather.” Under the weather hazard, you'll see options for fog, hail, flood, ice on road, and unplowed road.
Tap any of the forecasts and it'll show you more detailed data such as humidity, wind speed, visibility, precipitation, and what temperature it feels like outside. Weather on the Way is free for iOS.