Tribhuvan International Airport turbulence forecast
Kathmandu, Nepal
KTM (Kathmandu, Nepal) sits at 27.70°N, 85.36°E, 4,390 ft elevation — coastal with the Himalayas nearby.
About KTM
Major airport serving Kathmandu, Nepal.
- Climate
- Subtropical coastal — mild winters, humid summers
- Nearby terrain
- Himalayas
- Geography
- Coastal — marine-influenced airmass
What to expect on departures
Computed from KTM's geography and climate
The 4,390 ft elevation puts KTM above most of the densest surface air, so initial climb is brisk but the airport itself sits inside any low-level turbulence patterns. The jet stream meanders across this latitude seasonally — KTM sees its strongest CAT exposure in December–February, when the polar jet pushes equatorward and routes intersect it more often. June-onwards departures climb into cleaner upper-level flow. The Himalayas sit upwind of KTM on prevailing flow days, generating mountain-wave turbulence that can extend several hundred kilometres downwind at cruise level. The lee-wave risk is highest when December–February winds at FL300 cross the Himalayas at near-perpendicular angles. Monsoon months pump moisture and instability into the local airmass — expect significantly more convective turbulence during the wet season at KTM, with much smoother cruise during dry-season operations. KTM's coastal position means departures often transit from the cool marine boundary layer into warmer continental air within minutes of takeoff — a brief but reliable bumpy transition on warm-season afternoons when the sea breeze is set up.
Climbout notes
Standard Instrument Departures (SIDs) often route around terrain; on strong-wind days, low-level turbulence in the lee of the hills is common in the first few thousand feet.
Seasonal pattern
Winter (December–February) brings the strongest jet-stream activity — that's when long-haul departures most often log clear-air turbulence at cruise. Summer (June–August) is peak thunderstorm season — convective turbulence is the dominant warm-season risk. Mountain-wave activity near the Himalayas peaks in the cold season when upper-level winds blow hardest across the range.
- Peak turbulence
- Monsoon months (varies by hemisphere)
- Typically calmest
- Dry season
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KTM turbulence FAQ
Is turbulence common on flights from KTM?
Tribhuvan International Airport is best described as a mountain-wave sensitive airport. The 4,390 ft elevation puts KTM above most of the densest surface air, so initial climb is brisk but the airport itself sits inside any low-level turbulence patterns.
When is turbulence worst for Kathmandu flights?
Winter (December–February) brings the strongest jet-stream activity — that's when long-haul departures most often log clear-air turbulence at cruise. Peak turbulence window: Monsoon months (varies by hemisphere). Typically calmest: Dry season.
Does the terrain around Kathmandu affect turbulence?
Yes — the Himalayas lie close enough to generate mountain-wave turbulence on days with strong upper-level winds. These waves can propagate hundreds of kilometres downwind, so they sometimes affect cruise even after you've left the immediate area.
How accurate are Turbcast forecasts?
We combine live NOAA Aviation Weather Center data (PIREPs, SIGMETs, AIRMETs) with physics-based Ellrod and Richardson-number calculations derived from Open-Meteo pressure-level wind and temperature data. If a source is unavailable for a waypoint we show an em dash rather than invent a number.
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