Inconsistencies between T2m and mn2t3,mn2t6/mx2t3,mx2t6 fields after interpolation to station points

Datasets and Usage Open data
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Hello ECMWF community,

I am working with ECMWF Open Data (HRES) and extracting station-based time series from GRIB2 fields. For temperature, I use:

  • t2m – 2 metre temperature (instantaneous at the forecast step)

  • mn2t3 / mn2t6 – minimum 2 metre temperature over the past 3h / 6h

  • mx2t3 / mx2t6 – maximum 2 metre temperature over the past 3h / 6h

All variables are interpolated consistently to station coordinates using the nearest-neighbour method.

Sometimes I observe that at the same forecast step:

  • T2m ≤ Tmin or T2m ≥ Tmax

which looks counter-intuitive because the instantaneous value should normally lie within the min/max window.

I may be misunderstanding how these parameters are defined or processed, and I would like to ask for your help to clarify this issue. Is this behaviour expected, or does it suggest that I am doing something incorrectly in my extraction? What would be the best practice when users need Tmin/Tmax at specific stations?

Any guidance or references would be greatly appreciated.

Thank you very much!