Yes almost ISA in this case, but just an example. But in most cases the ISA temperature delta would be good enough problably.

This graph is from meteblue, it's only available for point+ subscriber i think.

Regards,
Simon

Wouldn't it be even more accurate to use the result of the model for the exact elevation?

So for example Mont Blanc: The delta between ECMWF model elevation and real elevation:1101m:

So to get the estimated temperature/wind at the summit: use the closest calcuated value to 1101m above model surface. That's certainly also not 100% correct, because it doesn't take surface effects into account, but maybe more accurate than to assume ISA.
It don't have access to the ECMWF data, but here a snapshot from NEMS4 sounding for Mont blanc:

The NEMS4 model surface seems to be at ca 3200m according to this sounding, temperature around -5°C.
At 4800m it shows like -15°C. So a delta of -10°C in this case.

Regards,
Simon

I made a small research and I provide you the data and conclusions
(for ECMWF model).
Chamonix: model's "surface" =2137m, elevation=1036m (Δ= 1101)
Mont-Blanc:model's "surface" =2265m, elevation=4808m (Δ= - 2543)
Temperature adjustment
Chamonix: +7,1C
Mont-Blanc: -16,5 C.
Those "adjustments" take into account Standard Atmosphere's lapse rate (6,5/1000m).
In the real world, the lapse rate may vary from 9,8 °C/km in dry air
to around 5 °C/km for moist air (into clouds).

Hope it helps

Also for Zugspitze (actual=2962 m , model's reference alt.=1700m).
Difference 1262m, temp. adjustment - 4 C (aprox).

Thanks for the link. That's exactly the same issue in fact

Hi,
sorry i didnt mention that i also selected the NEMS4 model at windy. And i made the observation that it shows completely different surface values than other weather websited that use the same models - in alpine areas.

This was very evident during the past days with strong winds. The windity map just didnt show these high gusts speed that you'd expect on mountains - while other weather websites with same models delivered far better results.

The Airgram helps here - like the elevation slider, but it doenst show the elevation of the model data for this position. In fact, it seems that the pressure scale is hard coded? Otherwise it wouldnt make sense that the air pressure scale f.e. at Mont-Blanc starts at 1000hpa. I'd first need to calculate the current air pressure at the real surface level there.

I just felt the urge to give this feedback. Because despite the really nice frontend, the great usability of windy.com and the state-of-the-art weather models this is quite a weakness if you look for forecasts in mountain areas.

Regards,
Simon

Hi, thx for the reply - this explanation makes sense.
The "average elevation" of the models seems to raise very slowly, so at the main ridge of the Alps the temperature gets lower. While only single elevation peaks aren't mapped in these models accurate.

But by combining these model results with high resultion terrain maps (like here at windy) there should be way to extract more accurate numbers from the model.
Here's a snapshot from the meteoblue map for this area, which shows also the NEMS-4 model, but appearently maps the model results better on the terrain:

Or a simpler idea. It would already help to display the model surface elevation for a selected position. Than you could just calculate the delta from the real elevation to the model elevation and adjust the slider at the right side.

Regards,
Simon