there are a number of sites with the same 191 days rain data, but no reference.
However, the Royal Botannical Gardens Edinburgh have their own weather station.
Data is available here:
http://www.rbge.org.uk/science/plants-and-climate-change/edinburgh-weather-station
more relevantly, their extract “Some curiosities from the RBGE Inverleith weather station:
Data analyses from 1 January 1976 to 31 December 2014. “
http://www.rbge.org.uk/assets/files/science/Weather/InverleithCuriosities2014.pdf
States:
Days with no rain 41.1%
Days with 0.2mm or more 51.2%
Days with 1mm or more 36.0%
Days with 5mm or more 14.0%
Depending on your personal definition of “rain day”, it suggests that IF rain days are consistently seasonally distributed* over the 38 yrs of the data set, that 214 days a year have “some” precipitation.
* and they may well not be, there may have been 4 yrs in the 70s in which it never stopped raining which will skew the data, unless they really do mean that in an average year, only 41% of days are dry….
Not forgetting that a day is 24hrs, and many incidents of precipitation will have been overnight. TJ may well be right anecdotally (with bias, natch) and statistically wrong at the same time, but they may not really be inconsistent depending on definitions.