Every weather app shows you the forecast at a single point. But if you're driving, riding, or cycling 100 miles, that's not actually the information you need, what you need to know is what the weather will be at each part of your route, at the time you'll be there.
ClearRide takes a route and a departure time and shows you the weather along the whole route, which rain bands you'll hit, temperature changes, wind shifts. Mostly useful for spotting a 20-minute rain window you'll ride into at the halfway point that no point forecast would warn you about.
Built it because I'm a year-round motorcycle rider in the UK and got tired of being ambushed by weather that "wasn't in the forecast", well it was, just not in the forecast for where I was standing.