RunWeather vs Weather Underground for runners

Weather Underground (WU) is the weather app for people who like data. Its website counts more than 400,000 personal weather stations, its hourly forecast on the web shows dew point and feels-like for every hour, US users can switch to the National Weather Service forecast, and Premium ($19.99 a year on iOS) stretches the hourly forecast from 10 days to 15.

Its closest feature to RunWeather is Smart Forecasts, part of Premium: you "set your ideal weather conditions" for an outdoor activity and the app tells you when to go. That works, but you write the rules yourself. RunWeather ships the rules: a 0-100 Run Score for every hour from a published model that weighs dew point, WBGT heat strain, wind and rain, with hard safety caps, plus the pace cost of the hour you pick.

Want the detail behind the scoring? How the Run Score works publishes every threshold the model uses.

When Weather Underground is the better pick

If you want to see what the station down the street reads right now, track a storm on radar, compare against the National Weather Service, or plan more than a week out, WU is the stronger weather app. Smart Forecasts also covers any outdoor activity, not only running, if you are happy to set the limits yourself.

When RunWeather earns its place

If you run most days and want the call made for you: which hour is best, how much the dew point will cost your pace, whether heat strain crosses a safety line. RunWeather publishes every threshold it uses, so you can check the reasoning instead of tuning your own. It also looks back: it reads your runs from Strava, Apple Health or Health Connect and shows what the weather did to them: your latest run free, every run with Pro.