I would like to calculate the prior probability of active precipitation currently taking place at any random moment during a year.
The area I’m looking at (London, UK) has averages of 601.7mm of rain and 109.6 precipitation days per year (according to https://en.m.wikipedia.org/wiki/Climate_of_London).
I haven’t been able to find any historical data for “time spent raining”, nor for average the distribution of rain intensity (which would also help me estimate this), for any area. Is this data publicly available anywhere?