Student Contributors: Ryan Aylward, Mississippi State
University; Jordan Scampoli, St. Michaels College
Snow Days Summary:
Snowdays, much like snowfall, generally begin in October and go through April
with the peak in January. As shown in the snowfall section, Tupper Lake and Gouverneur have a larger
variance in snowfall in January, primarily due to lake effect snowfall.
More snow days are experienced in northern regions, with Rutland and Cavendish receiving the
least number of snow days. Normally, throughout the region in January, at least 10 days of snowfall
can be expected. Mount Mansfield has the greatest number of snow days, with up to a median value of
18 in January. The most extreme values are also found at Mount Mansfield, where 27 days of at least
0.1 inches of snowfall were recorded in January, 1978.
How to Read Box and Whisker Graphs
Box and whisker graphs are used to visualize the data. The intent of the box and whisker format
is to give a comprehensive depiction of the variable range, skewness, and extreme values. This
provides more detailed information about the variable than, say, a simple statistical mean would. It
also facilitates comparison between different months and station locations around WFO
Burlington's forecast area.
An example of the diagram format is shown at left. The shaded region of each graph (i.e.,
"the box") shows the middle 50% of the variable range. The top of the box is the 25th
percentile and the bottom is the 75th percentile. The solid line within the box indicates the median
(or 50th percentile). The lines extending upward and downward from the box (i.e., "the
whiskers") reach to the 10th and 90th percentile of the data distribution. That is, only 10% of
the data lies above and below the ends of the whiskers. Lastly, the "x" indicates the
extreme (record) value during the entire period of record for that particular location. The period
of record is often greater than the standard 30 year period used to create the box and whisker
portion of the graph (unless otherwise noted).