Istria 100 - 42K 2027
The forecast arrives five days before the start.
Here you'll find the elevation profile, an estimated finish time based on your UTMB Index and details of the 4 aid stations to plan your nutrition and hydration segment by segment.
What's your time based on your UTMB?
Times estimated by the RAVIT model, learned from real ultra-trail finish times. Enter your UTMB Index (utmb.world) to get a personalized estimate.
Predicted race time based on your UTMB Index® · smoothed times achieved by runners at your level in past editions
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Cut-off times and crew - Istria 100 - 42K · 2027
Data from the official race rules, checked for every edition. The race rules prevail. Positions are interpolated along the GPX track and are a guide, not official course marking.
What you'll find at each aid station
| Product | LIVADEkm 5.1 | GROŽNJANkm 20.9 | BUJEkm 27.8 | UMAGkm 42.6 |
|---|---|---|---|---|
| Water | available | available | available | available |
| Brand products · Näak | available | unavailable | unavailable | unavailable |
| Hot meal | unavailable | unavailable | unavailable | available |
La feuille de ton assistance pour Istria 100 - 42K · 2027
L'assistance n'est autorisée sur aucun poste de cette course.
Elevation profile
The course and its aid stations
Istria 100 - 42K: times, aid-station stops and fuelling needs by UTMB® Index
Between a UTMB® Index of 500 and 800, the estimated finish time on this race runs from 5h06 to 3h27. These times include aid-station stops: they come from real durations between two timing points, and this race's timing does not measure stops separately.
Source| UTMB® Index | Estimated time | Night hours | Carbs | Fluid | Sodium | Cut-off margin |
|---|---|---|---|---|---|---|
| 500 | 5h06 | — | 306 g | 3.6 L | 2,550 mg | +2h54 |
| 550 | 4h42 | — | 282 g | 3.3 L | 2,350 mg | +3h18 |
| 600 | 4h15 | — | 255 g | 3 L | 2,125 mg | +3h45 |
| 650 | 4h02 | — | 242 g | 2.8 L | 2,017 mg | +3h58 |
| 700 | 3h50 | — | 230 g | 2.7 L | 1,917 mg | +4h10 |
| 750 | 3h36 | — | 216 g | 2.5 L | 1,800 mg | +4h24 |
| 800 | 3h27 | — | 207 g | 2.4 L | 1,725 mg | +4h33 |
Figures based on 60 g of carbohydrate, 700 mL of fluid and 500 mg of sodium per hour, "average" preparation and mild conditions (15–25 °C). Above 25 °C, count on roughly 900 mL/h and 700 mg/h. Carbohydrate intake is trained: 60 g/h is a floor, 90 g/h assumes a glucose-fructose blend and a gut used to it.
Measured on the 2026 edition: the field checkpoint by checkpoint
682 starters, 4.3% DNF rate, 4 timed checkpoints.
| Segment | km | Median | Middle half | Measured | Median passage | Still ranked |
|---|---|---|---|---|---|---|
| Motovun → Livade | 5.1 | 35 min | 30 min – 38 min | 682 | 35 min | 682 |
| Livade → Groznjan | 20.6 | 2 h 20 | 2 h 02 – 2 h 39 | 680 | 2 h 54 | 680 |
| Groznjan → Buje | 27.4 | 55 min | 47 min – 1 h 05 | 668 | 3 h 51 | 669 |
| Buje → Umag | 42.2 | 1 h 53 | 1 h 39 – 2 h 08 | 652 | 5 h 44 | 653 |
“Median passage” is elapsed time from the start, not a clock time: the clock time depends on the edition.
Where runners drop out. Buje (16) · Groznjan (11) · Livade (2) out of 29 total DNFs.
RAVIT record from the official timing of the 2026 edition, data from September 22, 2026.
SourceIn the 2027 ranking
Istria 100 - 42K is 43 km and 1,039 m of elevation gain, that's 52 km-effort: category S, among 163 races in 2027. Its time limit of 8 h requires a minimum speed of 5.3 km/h: rank 111 out of 145 of the widest cut-off times in S.
S trails 2027: 45 to 74 km-effort
Similar effort in 2027
- Val Maremola Trail ed.15 - Val Maremola Long Trail ed.15 · 52 km-effort
- This ain't your mother's 50k · 52 km-effort
- Trails De La Vallée Du Brevon - AlloDuoTrail - relais 1 · 52 km-effort
Other trails worth preparing for
Sources and method
- Time projection — times by UTMB Index are taken from the actual splits of runners in each level band on previous editions of this race, aid station stops included. No formula is used as long as these results exist.
- Trail nutrition — hourly targets for carbohydrate, fluid and sodium follow the commonly accepted ultra-endurance guidance. La Clinique du Coureur — Fuelling in trail running
- Course, aid stations and cut-offs — taken from the event's official rules, which prevail in case of any discrepancy. Official site — Istria 100 - 42K
Weather for Istria 100 - 42K
The weather for Istria 100 - 42K will appear here as soon as the forecast models reach that date, around five days before the start: feels-like temperature, rain, snow, wind and storms, section by section and at your passage time.
Detailed weather for Istria 100 - 42K, hour by hour on the courseFrequently asked questions
How many checkpoints?
Istria 100 - 42K has 4 checkpoints: 2 aid stations and 2 water points. Details are in the two tables above.
What's the longest segment without aid?
The one leading to GROŽNJAN: 15.7 km and 0 m elevation gain. That's the one to load up for first.
How do I find the exact location of an aid station?
The Google Maps icon in the “Access” column opens the aid station's location: handy for planning your crew's routes.
What distance and elevation gain?
Istria 100 - 42K is 43 km long with 1039 m of elevation gain.
How long to finish?
With a UTMB Index of 600 (average runner), the estimated time is around 4h15 for Istria 100 - 42K.
What's the weather forecast?
The weather for Istria 100 - 42K will be published on this page around five days before the start, once the forecast models reach the race date. It will be detailed section by section: feels-like temperature, rain, snow, wind and storms.
Want to stack the odds in your favor for Istria 100 - 42K?
In 2 minutes, RAVIT generates your complete plan: segment-by-segment time, carbs, water and sodium at every aid station, printable roadbook.
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