On Thursday, 18 July 2013 14:00:26 UTC+1, exmetman wrote:
Dead right Graham - a meteorological drought.



Wikipedia says this about the 'old' definition:



"A drought was defined as 15 consecutive days with less than 0.25mm (0.01 inches) rain on any one day"



and as far as I can see it says this is the new improved version:



"A drought is usually defined as an extended period of weather (usually around 3 weeks) where less than a third of the usual precipitation falls"



As far as I can see the old method is very clear and the new method totally ambiguous with the use of the word "around" very imprecise...

You're quite right. The old definition had at least a certainty about it, and made people sit up and take notice when it was announced- partly,I suspect, because it has a Biblical ring to it.
While we're on the subject, in Bristol we've had 9" rain this year so far-2" more than last December-a fitting end to Bristol's wettest year since the 1850's