whtsky Hiking Weather
Altitude-aware weather forecasts for hiking routes using Open-Meteo (free, no API key).
Core Workflow
1. Determine Route Info
Most users will just say a mountain/trail name. Work with whatever they give:
Typical: user gives a mountain or trail name
Search for: coordinates, trailhead elevation, summit/highest point elevation. This is enough — no GPX needed.
Example: "Tongariro Alpine Crossing" → trailhead 1120m, summit 1868m, coords -39.135, 175.651
If user gives coordinates + elevation range, use directly.
If user provides a GPX file (advanced):
python3 scripts/parse_gpx.py <file.gpx> --max-points 8
If output shows needs_elevation_lookup: true, fill elevations:
curl -s "https://api.open-meteo.com/v1/elevation?latitude={lat1},{lat2}&longitude={lon1},{lon2}"
2. Select Pressure Levels
Map route elevations to pressure levels. See references/open-meteo-api.md for the altitude↔pressure table.
Rules:
- Always include one level BELOW route minimum and one AT or ABOVE route maximum
- For a 1100–1868m route: use 900hPa (
1000m), 850hPa (1500m), 800hPa (~1900m) - For a 2000–3776m route (e.g. Fuji): use 800hPa, 700hPa, 600hPa
3. Fetch Weather Data
Build the Open-Meteo API call. See references/open-meteo-api.md for full parameter reference.
Essential variables:
- Surface:
temperature_2m,apparent_temperature,precipitation_probability,precipitation,snowfall,weathercode,cloudcover,cloudcover_low,cloudcover_mid,cloudcover_high,visibility,windspeed_10m,windgusts_10m,winddirection_10m,freezinglevel_height - Per pressure level:
temperature_{level}hPa,windspeed_{level}hPa,winddirection_{level}hPa,cloudcover_{level}hPa,relativehumidity_{level}hPa
Set elevation parameter to the summit elevation for accurate surface forecasts at the highest point.
4. Analyze and Present
See references/safety-thresholds.md for go/no-go criteria.
Output format (adapt to context — Telegram, Discord, etc.):
🥾 [Route Name] — [Date]
📍 [Elevation range]m
⏰ Best window: [time range]
[✅/⚠️/🔴/❌] Overall: [go/caution/risky/no-go]
Summit ([elevation]m, ~[X]hPa):
🌡️ [temp]°C (feels [apparent]°C)
💨 Wind [speed] km/h, gusts [gust] (direction)
☁️ Cloud [%]% at summit level
👁️ Visibility [X] km
❄️ Freezing level: [X]m [above/below summit]
🌧️ Precipitation: [%]% chance
Trailhead ([elevation]m):
🌡️ [temp]°C
💨 Wind [speed] km/h
📋 Gear notes:
- [wind shell / warm layers / rain gear / crampons etc.]
⚠️ Alerts:
- [any concerning conditions]
Key analysis points:
- Compare freezing level to summit elevation → ice risk
- Check cloud cover at summit pressure level → visibility/view quality
- Cloud cover below summit + clear at summit = potential cloud sea 🌊
- Wind at summit level vs surface → ridge exposure risk
- Identify best weather window (typically early morning)
- If multi-day forecast requested, recommend best day
Critical Rules
- Always use pressure level data for summit conditions, not just surface
temperature_2m(which is corrected to the elevation parameter but doesn't capture cloud/wind layering) - State the data source and forecast time clearly
- Never say "probably fine" — use the threshold table and be specific
- If conditions are marginal, recommend early start and turnaround criteria
- For multi-day hikes, check each day and each camp elevation separately