Portes d Onne-1920
📍 Rhone-Alpes , Departement de la Haute-Savoie · Nearest city: Chatel (2 km)
61 XC score / 100 · takeoff at 1920 m · 📍 View on map
Coordinates and external links
46.28260, 6.86450Forecast next days
Updated: 2026-04-20 13:22 UTC · Source: Open-Meteo · Thermal window 10:00–18:00 local time
Día muy favorable para XC, base de cúmulos ~986 m, viento 9 km/h.
base ~986m · wind 9 km/hDía muy favorable para XC, base de cúmulos ~698 m, viento 14 km/h.
base ~698m · wind 14 km/hDía volable, condiciones decentes, base de cúmulos ~1301 m, viento 11 km/h.
base ~1301m · wind 11 km/hDía volable, condiciones decentes, base de cúmulos ~1537 m, viento 12 km/h.
base ~1537m · wind 12 km/hComposite flyability score (CAPE + LI + wind + precip + low clouds). Cross-check with local pilots before flying.
Detailed hourly weather
2026-04-20❌ Not recommended · peak 55 at 10h
- Cobertura nubosa >85% — sin radiación para disparar
- Cloud suck alto (100/100) — base bajo freezing con CU
⏰ Useful window: 13:00 – 15:00
| 08 50 | 09 50 | 10 55 | 11 40 ☁️⚠️ | 12 45 ☁️⚠️ | 13 45 ☁️⚠️ | 14 45 ☁️⚠️ | 15 45 ☁️⚠️ | 16 55 ☁️⚠️ | 17 50 ☁️⚠️ | 18 50 ☁️⚠️ | 19 50 ☁️⚠️ | 20 50 ☁️⚠️ |
Peak 10h: CAPE 0 J/kg · LI 1.0 · BL top 780 m · w* 0.0 m/s · cloud base 2295 m · 0°C at 2600 m · Pro score 78/100 · sun 35° over slope
2026-04-21⚠️ Marginal · peak 55 at 9h
- Cloud suck alto (100/100) — base bajo freezing con CU
| 08 35 | 09 55 ☁️⚠️ | 10 50 ☁️⚠️ | 11 55 ☁️⚠️ | 12 55 ☁️⚠️ | 13 45 ☁️⚠️ | 14 40 ☁️⚠️ | 15 45 ☁️⚠️ | 16 40 ☁️⚠️ | 17 40 ☁️⚠️ | 18 35 ☁️⚠️ | 19 30 ☁️⚠️ | 20 35 ☁️⚠️ |
Peak 9h: CAPE 0 J/kg · LI 3.7 · BL top 340 m · w* 0.0 m/s · cloud base 2420 m · 0°C at 2380 m · Pro score 73/100 · sun 31° over slope
Hourly flyability (0–100). ⛈️ = storm risk · ☁️⚠️ = cloud suck · 🏔️ = active ridge lift. CAPE = convective energy, LI = stability, BL top = thermal ceiling, w* = estimated dry thermal velocity. Source: Open-Meteo (ECMWF/GFS/ICON blend model).
Estimated vertical profile (Sounding)
Reference time: 10:00 (peak of the day)
Surface T: 4.3°C · Td: 1.3°C
LCL (cloud base): 375 m
BL top: 780 m
0°C level: 2600 m
Approximate profile from surface variables + synoptic levels. Red lines = temperature, dashed blue = dew point. Orange bands = detected inversions.
Wind chart — altitude × time
Color: green < 20 km/h · yellow 20-30 · red >40. Arrows point to where the wind is blowing. Each column = 1 hour. 4 altitudes: 10m surface, 80m first thermal, 1500m (850 hPa) thermal cruise, 3000m (700 hPa) top.
Wind next days (Open-Meteo model)
Wind rose 10m — 2026-04-20
| Date | Morning 08-12h | Midday 12-16h | Evening 16-20h | |||
|---|---|---|---|---|---|---|
| 2026-04-20 | 5 km/h W | gust 24 | 8 km/h NW | gust 31 | 7 km/h NW | gust 31 |
| 2026-04-21 | 2 km/h N | gust 21 | 7 km/h NW | gust 27 | 7 km/h N | gust 26 |
Colors: green < 15 km/h (optimal) · orange 15-25 · red >25 (flying not recommended). ⚠️ = shear >25 km/h between 10m and 850 hPa (potentially broken thermals).
Takeoff orientations
Green = good orientation · Yellow = possible · Gray = not suitable
Why this site has thermal potential
| Factor | Value | Interpretation |
|---|---|---|
| Hotspot density (5 km) | 10 | High |
| Avg thermal probability | 0.85 | Based on thousands of aggregated IGC flights |
| Solar orientation | 0.38 | Slope faces south in northern hemisphere |
| Own flight history | 0.00 | Thermals detected in platform IGC tracks |
Pilot comments
More info on http://www.flyland.ch. Airspaces in Switzerland are a thought subject, get all the info you can get befire flying.
Nearby sites
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