Well what can you use?Rainfall totals are no good, you said you have taken time to look at plenty of data, you must know August 1981 then. A month on face value was wet but infact most of the rain fell on one night. There were a lot of dry days that month.This summer index was devised to gauge how good/bad summers were, it isn't full proof but I think it does its job pretty well.I devised the Manchester Winter Index, it's not full proof but I think it does its job sufficiently, last winter was the least wintriest for years and I think a lot of people would agree with this.