Plot time history of single/multi-month precipitation/temperature.

This program plots time series of multi-month accumulations of precipitation, or multi-month average temperature, based on divisional climate data for the U.S.
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.

**(April 2014)** Recent data set changes

Methodological/Data changes:
The entire dataset (1895-present) is being rebuilt.
The new dataset/database is based on 5km gridded data from GHCN-Daily and utilizes new methodologies for computing temperature, precipitation and drought for the CONUS.
Data from a larger array of stations is used which greatly improves data quality from the pre-1930s era.
For a general description of the data improvements and to investigate differences between the previously operational dataset and the current dataset, please visit the NCDC U.S. Climate Divisions webpage and explore the divisional data discovery tool:

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