Press and daily Dakotaian. (Yankton, Dakota Territory [S.D.]) 1880-1889, 1888-05-05
MAY PROBABILITIES.
Tenn perature, Predictinns and Chart of
General Weather Conditions.

Temperature, Pred;ctinns and Chart of
Genera Weather Conditions.
Obs var Felier, OF the signal office,
has prepared the ay issue OF the chart
mentioned last mouth, and will hang it
in the postoffioe. This chart is predic-
tive in character and o brief description
will enable it to be readily understood.
As stated before, the past gives valuable
indications for the future, and on this
fact the chart is based. The numbers
[ at the top of the chart indicate the day
of the month, aud those at the right
and left indicate degrees of temperature.
The three irregular lines across the
chart show the probable course of the
temperature through the month. The
upper one is the line of maximum tenn
perature, the middle the line OF mean or
average temperature and the lower one
the line Of minimum, or lowest tenn
perature. These three lines show the
same general course. though differing
slightly, as is to be expected. From
either OF them valuable Indications can
be deduced regarding the temperature
for May. Take for instance the upper
line. the probabilities are that the tenn
p%erature will increase until the 9Th day,
when q maximum will be reached, then
there will be a slight fall, aud minor
oscillations will take place until q second
maximum will be reached on the 17th.
Then a fall, and a gradual rise with
slight changes and another maximum
will occur about the 2Sth. This can OF
course be readily verified by zach days
experience, and its correctness verified
or disproved. The datea at the bottom of
the chart is self explanatory.
In order to show the reliability Of the
chart as q prediction, an enlarged form
OF the April issue has been prepared and
posted with the one mentioned above.
The black lines are OF the same char
acter as those on the May chart, and the
red ones are put in to show the tenn
p%erature as it actually did occur, maxi
mum, meal and minimum. Now
remembering that the lines do not indi-
cate the actual point to be reached by
the thermometer, showing the rise and
fall rather than their extent, and that
the difference OF q day in the occurrence
OF q maximum or minimum is not to be
wondered at, it will be seen that the
chart for April vas quite accurate i the
predictions. a slight rise was to cccur
with q maximum on the 3D.. The rise
took place with the maximum one day
later, and so OF the fall for the next day.
The maxima on the 9th, l4th and 18th
were each anticipated one day, The
fall on the 18th was as predicted.
The most striking v%erihcation for the
month was on the 21st. A very decided
rise wat predicted, eliminating on that
day, and 1t occurred as predicted. This
will be remembered as the warmest day
in April. Tho maxima on the Esd and
18th also occurred as predicted. These
charts will be issued every month, and
the chart for the preceding month will
have red lines added showing actual
course of temperature. Their productive
value is great, and while any particular
day may fail to show conditions just CO.
incident with those indicated, and
indeed, the whole month might fail like
wise, the chances are ell IN favor of q
range of temperature as indicated by the
chart.