Wind lull, as used by weatherflow is the mininum windspeed over certain period of time. When zooming out, weatherflow decided to change the period. That is totally weird/wrong. If weatherflow would make a graph of wind lull over the last 10 years it would be almost guaranteed to be a flat zero everywhere.
It shouldn’t do that. It should define some fixed period (say one minute), and define wind lull as the minimum over that period. When zooming out it should average the values, instead of taking the minimum again.
in general Weatherflow doesn’t like taking averages (see Data archive buckets explained) but often takes the closest observation. For things that don’t change very quickly that doesn’t matter too much.
With a new graphing system we can expect to see more then just 32 data points in a graph. (give me 500 or so 
) Lets hope that those data points are the ones with the highest sampling rate.