I urge caution when using average 'return period' data because the future pattern of precipitation and mean temperatures is unpredictable to the point that relying on historic data can be misleading and cause the general public to lose faith in the organisations that have appeared to make 'one-in-a- hundred year', 'one-in-twentyfive- year' type predictions. A short paragraph establishing the context of unpredictable variability should suffice to cover this point.