Windsplit · compared with other race-weather tools
Several tools price the weather into a race plan. This page lists what each one does, taken from their own pages, so you can pick the right one for your race. Windsplit is the free, browser-based option with wind per kilometre, drafting and a post-race replay.
| Windsplit | MeteoPace | racecast.io | Wind calculators | |
|---|---|---|---|---|
| Price | Free, no account | App with free tier; Race Pass $8.99 per race or Pro $39.99/year for the full pacing plan | Web race pages | Free web pages |
| Where it runs | Web, works on the phone; English and Norwegian | iOS and Android app, plus web race pages | Web | Web |
| Forecast | Open-Meteo, refreshed every 30 min from 16 days out; ECMWF ensemble spread as an uncertainty band; typical weather for the date before that | Forecast and historical averages per race | Forecast per race page | None: you type the wind speed yourself |
| Wind along the course | Per 100 m segment from the course bearing and the forecast hour you pass; headwind and tailwind priced separately | Wind shown per race with a wind chart; segment detail in the paid plan | Wind along the course via aerodynamic drag | One wind speed and direction for the whole run |
| Drafting | Alone, behind one runner, loose group or pack, and the share of headwind km you expect shelter on | Not listed | Not listed | No |
| Heat and sun | Effective temperature from air, solar radiation and airflow; humidity above 18 °C; three sensitivity settings; cost scaled by race distance | Heat impact shown; heat chart per race | WBGT-based heat | No |
| Hills | Minetti cost per 100 m from the course profile | Course profile with elevation | Gain, loss and altitude | No |
| Pacing output | Even-effort splits per km and per 5 km, finish-time mode, PNG plan for the phone, share link | Split-by-split plan and predicted finish (paid tier) | Expected pace and finish time | Wind-adjusted pace |
| Your own course | Upload a GPX; analysis runs in the browser | Curated races | Curated races | Any, by hand |
| After the race | Replay: Strava, GPX, TCX or FIT; wind, hill and heat cost per km; prediction vs result | Not listed | Not listed | Some convert a windy run to still-air pace |
Claims about other tools come from their own websites and app-store listings as of October 2026; "not listed" means the feature was not described there, not that it is missing. Tell us at [email protected] if something is out of date.
Running Writings, RunReps, The Pace Lab, BFL Coaching and Rundida each publish a calculator where you enter a wind speed and get a pace adjustment. They are quick for a what-if, and the physics is the same family as ours. What they cannot do is read the forecast, follow the course direction kilometre by kilometre, or credit the runner in front of you. Marathon Handbook's Chicago pace calculator does read the forecast and the street directions, for that one race.
Yes. Windsplit is free, has no account and runs in the browser. It gives wind cost per kilometre, drafting, heat, hills and even-effort splits for the curated courses and for any GPX you upload. MeteoPace is an app with free race pages and paid pacing plans, and covers more races.
No one has published a head-to-head test. Windsplit's wind model is calibrated to Davies (1980) and Daniels, drafting to Pugh (1971), heat to Ely & Cheuvront (2007) and El Helou (2012), and hills to Minetti, and every constant is listed on the tool's method page. Replay lets you check the model against your own races afterwards.
Yes. Any distance works with your own GPX, and the curated list includes half marathons and a 10 km. The heat cost is scaled by distance.
Yes. Løpsvær is the Norwegian edition with the same model and courses, at treningsverk.no/lopsvaer.