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Race IntelligenceDurban, South Africa

IRONMAN 70.3 Durban

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.

Race day
6 June 2027
Swim
1.9 km
Bike
90 km
Run
21.1 km

Published route evidence. Final 2027 route pending. Checked 14 Sept 2026.

Build my 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.

Your numbers
Distance unit
Weight unit
You and this race
Sharpen your range with more detailOptional. Recent swim, bike and run results, equipment and transitions.

Add only the evidence you have. Every control changes a discipline range, its uncertainty, or an execution-risk explanation.

Swim evidence

Replaces the broad pool-to-open-water assumption.

Bike and equipment

These replace broad mass, aerodynamics, tyre, and power-to-speed assumptions.

Run evidence

A recent effort and honest durability/acclimation answers refine the post-bike run.

Race execution

Transition proficiency changes the T1/T2 range and how wet conditions are treated.

What Durban actually gives you

You swim one anti-clockwise loop at uShaka Beach, ride two fast, undulating loops on the M4 highway between SUNCOAST Casino and Umdloti, then run multiple laps along the Durban beachfront promenade out to a South Beach turnaround. Ride the undulations evenly and the run stays available.

Show distances in

Swim

1.9 km

Single-loop Anti-clockwise Ocean Swim

Setting
uShaka Beach, near the Durban Harbour and uShaka Marine World

A calm, single-loop ocean swim at uShaka Beach gives a controllable, honest opening.

Source: 2027 current route

Bike

90 km

Two-loop Fast, Undulating Highway Route

Layout
2 loops
Setting
the M4 highway between SUNCOAST Casino and the Umdloti/M27 intersection

A fast, undulating two-loop highway route rewards a steady power number over reacting to every undulation.

Source: 2027 current route

Run

21.1 km

Multi-lap Beachfront Promenade Route

Setting
the Durban beachfront promenade, out to a South Beach turnaround

A multi-lap beachfront promenade rewards legs that rode the undulating highway bike evenly.

Source: 2027 current route
Where these course facts come from

These facts come from the organiser’s latest published material: swim, 2027 current route; bike, 2027 current route; run, 2027 current route. They describe the character of the course. They do not confirm the final 2027 route.

How I’d want you to race it

One job for each part of this course. The distance markers tell you when the job changes. The course tells you why.

Swim

Settle at uShaka Beach

  1. 0–300 m

    The start

    Find clean water early

    The calm ocean swim at uShaka Beach rewards an honest, controlled opening.

    • Seed honestly
    • Settle into rhythm

Bike

Ride the undulations evenly

  1. 0 km45 km

    First loop

    Ride the undulations evenly

    The fast, undulating M4 highway invites surging on every rise. Hold one steady power number instead.

    • Cap opening effort
    • Fuel early
  2. 45 km90 km

    Second loop

    Protect the run

    Repeat the first loop's effort and finish planned nutrition before the promenade run.

    • Stay patient
    • Finish planned nutrition

Run

Use the promenade laps

  1. 0 km10.5 km

    Toward South Beach

    Start controlled

    Let the outbound promenade laps feel easy, not fast.

    • Easy first aid station
    • Check posture
  2. 10.5 km21.1 km

    Back along the promenade

    Use what you saved

    Only progress once the outbound laps have held together.

    • Stay tall
    • Choose the last move late

What I would keep an eye on

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.

Forecast statusToo early for a forecast

A race-day forecast is not meaningful yet; check back closer to the event.

Temperature
14.5–23.6°CDew point centred on 11.8°C
Wind and gusts
11.2 km/hGusts up to 54.7 km/hPrevailing direction NW
Rain likelihood
Up to 55%Wet-surface uncertainty retained

Historical baseline, 2019–2025 · Open-Meteo historical archive · Updated 2026-09-14.Historical comparison only. This is not a forecast for 2027.

What goes into your range

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.

  1. Your numbersCSS · FTP · weight · run threshold
  2. This raceDistance · water type · elevation · exposure
  3. Your Race CardFinish and discipline ranges, with target paces and watts

Confidence is built from four inputs

Athlete evidence
Builds with recent open-water, bike and run efforts
Bike setup
Builds with equipment, mass, aero and tyre detail
Course evidence
Partial while the 2027 route is unconfirmed
Race-week conditions
Historical baseline until a forecast is useful
How the model works

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:

  • Your evidence: consistent inputs and recent race-like swim, bike, and run results.
  • Bike setup: measured or specified aerodynamics rather than a broad prior.
  • The course: verified distance and route character, including elevation and technical sections.
  • The conditions: a current forecast is more useful than a historical comparison.

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.

If Durban is your race

Your range is built on today’s numbers. The months of training before race day decide what those numbers become.

Sources and verification

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 2026-09-14.