Swim
1.9 km
Clear Alpine Lake Loop
- Setting
- Obersee, Rapperswil-Jona
A clear, calm Obersee loop gives a controlled start before the demanding bike ahead.
Source: 2025 previous-edition routeRace IntelligenceRapperswil-Jona, Switzerland
Know your day before you race it.
Enter four numbers you already train with. You get a likely finish range, target paces and watts, and how I would race this course.
Published route evidence. Final 2027 route pending. Checked 13 Sept 2026.
01 Race Card
Your first range uses conservative assumptions. Add optional evidence to make it more specific. It is calculated in your browser and saved only on this device.
02 The course
You swim a clear, calm loop in the Obersee, ride two hilly loops through the countryside around Rapperswil-Jona with demanding climbs and rewarding descents, then run through medieval streets and the lakeside Strandweg before the course's own named 'stairway to heaven' climb to the finish. This is a course that punishes anyone who treats the first bike loop as separate from the second.
Swim
1.9 km
A clear, calm Obersee loop gives a controlled start before the demanding bike ahead.
Source: 2025 previous-edition routeBike
90 km
Two hilly loops with demanding climbs mean the first lap's effort decides how much the second lap and the run actually have left.
Source: 2025 previous-edition routeRun
21.1 km
Medieval streets, the Strandweg lakeside and a named stepped climb reward legs that didn't spend everything on the bike's first loop.
Source: 2025 previous-edition routeThese facts come from the organiser’s latest published material: swim, 2025 previous-edition route; bike, 2025 previous-edition route; run, 2025 previous-edition route. They describe the character of the course. They do not confirm the final 2027 route.
03 Race plan
One job for each part of this course. The distance markers tell you when the job changes. The course tells you why.
Swim
The clear, calm lake gives a controlled start before the demanding bike ahead.
Bike
Ride the demanding climbs to a power cap. You will see this terrain again on lap two.
Hold the same effort on the repeat climbs and finish your nutrition before the run.
Run
Let the medieval streets and Strandweg lakeside feel easy before the course's own named climb.
The named stepped climb near the finish rewards legs that didn't spend everything on the bike's climbs.
04 Race week
There is no useful 2027 forecast this far out. For now, past race dates give us a point of reference. Closer to the race, the forecast will tell us whether the plan needs changing.
A race-day forecast is not meaningful yet; check back closer to the event.
Historical baseline, 2019–2025 · Open-Meteo historical archive · Updated 2026-09-13.Historical comparison only. This is not a forecast for 2027.
05 Method
Your CSS, FTP, weight and run threshold create the first range. Open-water, bike, run and execution evidence can replace broad assumptions. Course data and the historical conditions baseline shape every simulation.
Confidence is built from four inputs
It starts with the targets in your Race Card, then samples the parts of a 70.3 that vary: open-water pace, transitions, bike speed at the planned power, and the drop in run performance after the swim and bike. Repeating that calculation produces a likely range rather than a single heroic number.
The current time calculation uses this race’s published distances, or standard 70.3 distances where none are published, with the available course headings, elevation and exposure evidence. Weather scenarios vary temperature, dew point, wind, gusts, rain and water conditions together. Unknown route detail stays visible as uncertainty rather than false precision.
It is not predicting your exact finishing time, placing, or race-day weather. It answers a narrower question: given the plan and the information we have, what range of day is plausible, and where is the uncertainty coming from?
Confidence is not a permanent “low”. It is recalculated across four separate inputs:
It starts low when those inputs are broad. It can become moderate or high as the evidence improves. A narrower range means better information, not a guarantee.
Evidence
Course status: Partially verified. The organiser’s descriptions and latest published route profiles are in use. The final 2027 route is not yet confirmed. Last checked 2026-09-13.