The user selects the number of months to combine (1-72) and the ending month (that is, through the end of the ending month). For example, one could select the one month ending in July (that is, all July values in the record), the two months ending in January (that is, all Dec-Jan combined values in the record), the twelve months ending in December (that is, all annual values), or the forty-one months ending in April (for 1936, this would mean December 1932 thru April 1936, and for 1937 this would mean December 1933 through April 1937, etc.). Thus, for durations longer than a year, the data periods overlap.
For plotting purposes, the data are plotted on the ending year and month of the specified interval.
The individual years are shown in red lines.
The running mean is simply the average of the selected number of years centered on the plotted year. An odd number of years will be plotted centered on an actual year, and an even number of years will be plotted in between year values (for example, the 10-year mean for points ending in January 1986 through points ending January 1995 will be plotted at 1990.5).
The running means are shown as blue crosses.
The long term average, if selected, is shown as a green horizontal line.
Green dashes indicate plus and minus one standard deviation.
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