I remain a very simple controller and I may be way wrong here but that doesn't usually stop me.....
Although I am trying to persuade other posters - with a degree of subtlety, I hope - that reliance on IR W/V on short finals, in preference to ATC surface W/V reports, is generally NOT A GOOD IDEA; it's their accuracy and relevance that seem to me to be the problem, not their currency.
(1) IR HDG has to be instantaneous; most modern airliners do not possess flux valves, their only magnetic heading sensor being the ubiquitous E2B standby compass (or derivative of). IR HDG(T) is converted to HDG(M) by applying the local Variation. [The IRU knows where it is, and has a world map of Isogonals.]
(2) ADC TAS, being IAS-derived, is instantaneous AND not of declining accuracy.
(3) IR TRK is instantaneous for all practical purposes. How would the FMC know when to roll out of a turn otherwise?
(4) IR GS is also instantaneous; the platform constantly knowing the number and magnitude of accelerations it has experienced since last alignement.
As I understand it, an IRU maintains a position value for the aircraft. (I own up that I know very little about flux valves beyond what I learned from the film Back to the Future but years ago I did the 'How aeroplanes get around for controllers' course that tried to cover the principles of IRS and the like - but I may not have been listening closely enough.) If this assertion is correct other values used in calculations must be obtained from other sources, ADC for example, or derived by comparison with previous position information. Consequently, it seems to me that the TRK and GS vectors must be a historical value representing the average between the two positions used for the calculation. I would assume that for some purposes a longer period is better, (guessing a little here but...) perhaps for fuel calculations its good to know the progress of the aircraft over a longer period whereas when the FMC is determining where to end a turn a much shorter period is better.
If your aircraft are anything like ATC equipment, much of this is transparent to the operator and it works well most of the time. The comparison in the ATC world that immediately comes to mind is of radar tracking systems which, in simple terms, are designed to continue to display a target for a period even if the radar did not receive a response - the position of that target is based in what the tracking system 'expects' the aircraft to do. As I say, it works well most of the time but some systems will do strange things occasionally and knowing what the system is 'thinking' helps to understand why it happens and, maybe, how significant it is to separating aircraft.
Back to wind velocity on the flight deck - is an instantaneous value really what's outside at that vey moment, and if so, do you get any indications of variations? I can't speak for airports outside the UK but I think the wind report that you will get from the controller during the approach really does accurately reflect what is blowing across the TDZ - there's quite a lot of work involved in verifying that it does.