Autumn rainfall record

[Len Wood]

I attach a graph for my autumn (SON) rainfall record in Wembury 1985-2015.
There is a natural yearly variability of 76 mm as calculated from the standard deviation.

autumn 1.jpg (93.02 KiB) Viewed 61801 times

[Paul Swinhoe]

For comparison, here is a rainfall graph for the same period, but for Newcastle-under-Lyme in North Staffordshire. There is again a suggestion of an increase, but the very wet autumn of 2000 distorts things a little. Using a polynomial trend line (order 2) a different picture is suggested. During the same period, autumn temperatures also increased by over 1 degree Celsius.

[Len Wood]

It is certainly true Paul that autumn in year 2000 distorts the trend somewhat.

The linear fit trend line gives a magnitude increase of 44 mm over the period.

The natural yearly variability about the mean (as given by the standard deviation) is 76 mm.
So from a statistical point of view, the trend is not considered to be significant as it is below the variability.