A real race day, at a runner's pace
Know the heat before you run.
RunFast times the heat, humidity and dew point to your own pace, kilometre by kilometre along your route. Map it, fly it, share it.
Free. Save your runs, join your club’s page, and get each run’s forecast the evening before.
Your run, mapped.
Drop in any route from Strava, Garmin, Coros or your race's website, pick the day and your pace, and see what the weather will do to you, kilometre by kilometre. Try it right here.
What actually slows you down.
Heat stress at your pace
One number for heat, humidity, sun and wind: WBGT, the reading race medical teams set their flags by. Worked out for every stretch at the hour you'll reach it, with the hills timed the way they really run.
Dew point, the runner's number
How sticky the air is, on the scale runners already go by. Above 18° your sweat stops cooling you, and the same pace costs more.
Feels like, on the run
At running speed there's little breeze to cool you, so a sunny 26° climb can feel like 33°. And on a cold start at 05:30, the chill you'll dress for. Both worked out at your own pace.
They'll know you're at Fields Hill.
Race day starts in the dark. Your people follow you on a map, with your pace, the heat where you are, and when you'll reach the next landmark and the finish. No app needed on their side.
- Drummond, halfwayLow · 19° feels like10:36
- Botha's HillModerate · 24° feels like11:13
- Fields Hill, nowModerate · 27° feels like · 6:58 per km12:41
- Cowies HillExpected13:39
- Finish, DurbanExpected15:30
Every club run, with its weather.
Your club gets its own RunFast page with every club run on it. Members tap a run to see the weather on its route for that day and hour, at their own pace, and tap whether they're in.
- Every run on one page. Long runs, track nights, hill repeats and time trials, with their start times and routes.
- The weather for that run. The route coloured by how hard the weather makes it, at each member's pace, from 10 days out.
- Who's running. Members tap I'm in or Can't make it, and everyone sees the count.
See a demo club page · Run a club? Tell us about it and we’ll set up its page.
Every race day since 2015.
The Comrades, Berlin, London and Boston, on the day they were run, with the real weather hour by hour. Set your finish time and see what you'd have met at every landmark.
The Comrades, at your pace.
The down run, Pietermaritzburg to Durban, 90 km. Real weather on the second Sunday of June.
Run it before you run it.
Free on the web and in the RunFast app: save the routes you run, join your club’s page, and get each run’s forecast the evening before. The Android app, with live tracking for race day, is out now at runfast.tech/android; the iPhone app is coming to the App Store. One account works on all of them.
Also a cyclist?
RunFast's sister, Windline, rates every ride Good, Fair or Tough for the wind, timed to when you'll reach each stretch. Tours, races and club rides. Free on the web and Android.