Newspapers are the obvious source but thin out as one gets further back.
One resource that is clearly a labour of love, records Historical Weather Events in the UK, collected (it looks like) from a variety of sources.
However, note the warning on that screen that the site will disappear at some point. All is not lost, however, as it is one of those archived by the British Library. Go to the UK Web Archive and enter 'Booty Meteorological' in the search box ( _make sure there is no extraneous text - for whatever reason I seemed to fail dismally at that on several occasions - possibly too impatient to clear out the prompt_ ). Follow the links on the resulting site for "Meteorology", then "Weather in History / Here".
However you get to the data, it's pot luck whether you find anything for your era and area, but I'm impressed with what's there.