70.3

IRONMAN 70.3 Portugal-Cascais

Saturday, 17 October 2026

IRONMAN 70.3 Portugal–Cascais is a 1.8 km freshwater swim, a rolling 90.1 km bike with 562 m gain, and a 21 km rolling run—where W wind and moderate air temps reward steady pacing and on-target fueling.

· 13 days to go
Air
16–21°
typical
Wind
6.3 W
prevailing
Water
18.7°
typical — confirm
Bike climb
+562 m
Race-day forecast — 13 days outupdated 6h ago
14–22°
temp
30 km/h
wind NE
7%
rain chance
0 mm
rain total
05:00
☀️
15°
24 NE
☂ 6%
06:00
☀️
14°
23 NE
☂ 6%
07:00
☀️
14°
22 NE
☂ 6%
08:00
☀️
15°
21 NE
☂ 6%
09:00
☀️
16°
21 NE
☂ 5%
10:00
☀️
18°
20 NE
☂ 5%
11:00
☀️
20°
20 NE
☂ 5%
12:00
☀️
21°
19 NE
☂ 4%
13:00
☀️
22°
20 NE
☂ 4%
14:00
☀️
22°
21 NE
☂ 4%
15:00
☀️
21°
22 NE
☂ 5%
16:00
☀️
20°
25 NE
☂ 5%
17:00
☀️
19°
27 N
☂ 5%
18:00
☀️
18°
29 N
☂ 6%
19:00
☀️
18°
30 N
☂ 6%
20:00
☀️
18°
29 N
☂ 6%
21:00
☀️
18°
27 N
☂ 5%
Sunrise 07:48 · Sunset 18:56 · UV max 5 · gusts to 63 km/h
Actual forecast for this race date — refreshed daily as it approaches. The chips above are the 10-year typical.
Fueling — per hour
early outlook · 13 days out
90 g
carbs
700 mg
sodium
-50 mg vs typical
600 ml
fluid
-50 ml vs typical
  • 👍 Conditions are kind — the 600 ml/h fluid, 700 mg/h sodium and 90 g/h carbs baseline should hold. Fine-tune to your own thirst and sweat rate.
Build your fuel plan — which gels, how many per hourFuel tool →
Based on the race-day forecast (feels-like up to ~18°) — sharpens as the race nears. Baseline for a ~5.5 h finish, 70 kg athlete. Scale to your own body mass and sweat rate.

Typical 10-year conditions, not a forecast. Water temperature and the wetsuit ruling are set on race morning — check the IRONMAN race guide →

Worlds qualification — 50 slots at this racesee who qualified →
0 km45 km90 km191 m
90.1 km · +562 m climbing
T1 — swim to bike

Own the swim→bike transition: get from wetsuit/gear handling (if applicable) to momentum fast, then settle your cadence within the first few minutes. Approach the mount calmly, clip in promptly, and start with a smooth build rather than hammering. In the first 10–15 minutes on a rolling course, aim to keep power stable over the rises and avoid spiking effort on every change in terrain; save legs for the later undulations.

During the bike

Ride 90.1 km with 562 m elevation gain on rolling terrain, so expect repeated demand changes rather than long steady flat pacing. With wind around 6.3 m/s from the W, plan to be slightly more conservative when it’s exposed—especially if there are stretches that put you broadside—then use the calmer moments (and drafts you’re permitted to use safely) to recover and stabilize your breathing. Your fueling target per hour is 90 g carbs, 750 mg sodium, and 650 ml fluid—start hitting it early and keep it consistent, rather than waiting for hunger. Take in fluids with your carbs so you can keep intake smooth while you’re working the hills and holding steady on the flats; if you miss early numbers, don’t try to “catch up” by overshooting all at once—smooth the remainder.

Closing notes

The key is arriving to T2 with legs that still feel “available”: control surges on the rolling profile and keep fueling on-time through the back half so the run starts fueled.

Results by year

Every edition of this race in our database. The course and conditions can shift year to year — see who qualified and the World Championship slot rolldown for each.

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Weather is a 10-year climatology (typical, not a forecast). Course tracks are approximate, derived for planning — verify against the official course. Maps © OpenStreetMap. Not affiliated with or endorsed by the IRONMAN Group.