# ERA5 Data - How is a wind gust defined?

I'm working with wind data, that I buy from a company, which delivers basically reformatted ERA5 weather data from ECMWF (https://www.ecmwf.int/). Their historic wind data includes "Wind gusts (sfc)" (m/s) and I cannot find out how this "Wind gust" is defined.

My understanding is that a wind gust is basically just the maximum value of wind velocity of a number of averages within an observation period. Say I measure wind velocity as average over 1 hour, then look at the 10-minute averages of that same 1 hour and the largest of those is my "Wind gust" (V_600_3600 - see here for nomenclature: http://ijsetr.com/uploads/621345IJSETR1044-354.pdf).

But the ERA data are a re-analysis so of course the gust is basically just a factor on top of the average 1hour wind. What I cannot figure out, is, which gust definition this uses. Is it 10-min (V_600_3600) or 1-min (V_60_3600) or even 3-seconds (V_3_3600).

The support of my data-company insists that "Wind gust" is "the maximum wind velocity within an hour" (they deliver hourly data over long time periods - years) but they insist that this "Wind gust"-value cannot be defined in terms of a particular averaging-time period like 10-minute gust or similar.

I tried to find the wind gust definition for ERA5 - the only thing I found is this definition here, that defines the "Instantaneous 10m wind gust" as being equal to the 3s wind gust (V_3_3600): https://eqc-cms.predictia.es/pub/qar/reanalysis-1412/pdf

Is this the correct definition? I'm a bit confused, since this contradicts the company support guys (which are specialist for this thing). They insist, there is not time-averaging-period attached to the definition of "Wind gust" which is, in my understanding, not sensible. There must be some time information attached to any definition of "wind gust" as far as I understand? But then again I'm not a meteorologist and might miss something basic.

Obliged for any help to clarify this respectively lets me understand this better.