Runna, a popular running coaching app based in the UK, has launched a feature called Adapt for Heat. It automatically changes your workout based on how hot and humid it is where you live. The feature is available to all Runna subscribers as of July 29, 2026 (Engadget, Runna).

The way it works is straightforward. The app looks at your past training data and adjusts your workout specifically for you. It does not just apply the same change to everyone in the same city. A long, hard run and a short, easy run can be adjusted differently, even when the weather is the same (Runna).

In practice, this usually means the app tells you to run slower. It does not cancel your workout or move it to another day. Instead, it changes your speed target so that running in the heat feels about as hard as the same workout would feel on a mild day. The app also shows a color-coded forecast of the hottest and coolest hours, so you can pick a better time to run if you want (Engadget).

Runna also announced two more features coming in August 2026. One is called Upcoming Plans, which lets you create multiple training plans up to a year ahead. This is useful if you are training for more than one race or working toward a big goal. The other is a new and improved Post-Race Recovery Plan that gives you personalized guidance on how to recover after a race (Runna).

Together, these three features show where Runna is headed: building more of what a human coach does directly into the app. Adjusting workouts for hot weather is not a new idea in running. Coaches have done it manually for decades. What is new is that Runna does it automatically, using live weather data and your own training history, without needing a person to make the call.

There is a trade-off worth thinking about. The app adjusts your speed but keeps the workout itself the same. So if it is 35°C with 70% humidity, you still do the same run, just slower. That helps you avoid pushing too hard in the heat, but it cannot stop heat illness on its own. The runner still has to pay attention to how they feel and decide whether it is safe to go out at all.

There is also a question about new users. Because the feature relies on your past training data to make personalized adjustments, it may not work as well for someone who just signed up and does not have much history in the app yet. Runna has not said how much data it needs before the personalized adjustments kick in. Sharing that kind of detail would help users know how much to trust the feature.

For people already using Runna, the practical effect is simple: on hot summer days, your pace targets should now feel more realistic for the weather, instead of being set as if it were a perfect day. Whether that leads to better training results and fewer heat-related problems over time is something the app's own data could eventually show.

The August features round out a coaching experience that now covers planning months ahead, adjusting for the weather on a given day, and recovering properly after a race. Similar tools exist in other apps, but Runna is betting that bringing all of them together in one personalized system is what will set it apart.