Evening star. [volume] (Washington, D.C.) 1854-1972, 1889-07-11
WARM SUMMERS.
An Inquiry as to Whether They Really
Follow Warm Winters.

From Science
Almost every newspaper Of Boston has re-
Gently had something to say about what the
weather is to be during the coming summer
and 1t seems to be an almost unanimous con-
clusion that the following summer is TO be
warm because the winter and spring have been
warm, or because last summer was cool. This
has led Mr. H. H. Clayton to examine the tenn
perature observations made in Milton during
the last forty years by Mr. Charles Breck.
These observations have been made twice
daily from the same thermometer, hanging in
the same place since the beginning Of the OBJ
servations in January, 1s49. During the forty
years nineteen winters have been warmer than
the average, and eight Of the following sum-
mers have been warmer than the average
There have been eleven cases in which both
the winter and spring have been warmer than
the average, and following these there have
been five summers warmer than the average
There have been six decidedly warm winters:
that Is, winters whose mean temperature was
three degrees or more above the average; and
four of the following summers have been
warmer than the average. 1t is seen, then,
that only about half of the warm winters were
followed by warm summers; or, in other words,
cool summers have followed warm winters, as
often as the reverse. The number of times
warm summers have followed cool summers is
nine while the number of times cool summers
have followed cool summers is twelve.
In the above what has been called a warm
winter is one in which the mean temperature
OF the three winter months-December. Janu-
airy and February-has been higher than the
average OF forty years, and what has been
called a cool summer is one in which the mean
temperature of the three months of june
July and August has been lower than the
average of forty years, &c. This, however, is
evidently not the definition adopted by people
generally in deciding whether a winter or
summer is colder or warmer than usual, for a
decided departure of the temperature of
single month in any direction may determine
the impression people retain Of the entire sea-
son. Thus it will surprise most people to learn
that the mean temperature Of last summer was
slightly higher than the average of the last
forty years. Both June and August were
warmer than usual and only July was very
cool. 1t will probably be a still greater sur
prise to learn that the winter of 18S7-S8 which
was generally thought to be a cold winter, was
really slightly warmer than usual. December
usual, and January alone was very cold.
Thus peoples opinion of a season seems
to be largely moulded by the special
character of what is usually the most extreme
month of the season. II in winter January
happens to be exceptionally warm or cold, the
winter is decided to be of the same character;
or if July happens to be decidedly warm or
cool, the summer is thus characterized 1t
seemed, then, worth while to ascertain from
Mr.. Brecks record how many warm Julys fol-
lowed decidedly warm Januarys. There were
eight Januarys during the forty years whose
average temperature was above 80 degrees and
following these were five Julys warmer than
the average OF forty years, which indicates but
slight tendency for warm Julys to follow
warm Januarys, since the law of chance would
indicate that four warm Julys ought to fellow
eight warm Januarys. The number of times
warm Julys have followed cool Julys is twelve
and the number of times cool Julys have fol-
lowed cool Julys is eight
Another method frequently used in predict
ing the weather of a coming season il based
on the conclusion that during every year the
average conditions remain about the same;
and if the first part of the year is very warm
the latter part must be COOL This assumption.
however, appears to be entirely unsupported.
Mr.. Breck's observations show that the mean
temperature of one year may differ as much as
five degrees from another. Eleven months of
1877 were observed to be warmer than usual
and nearly as great departures in the opposite
direction were found in other years.
All Of these facts indicate that no conclusion
OF any value gre,ter than could be gained by
mere guessing can be formed in regard to the
character of a coming season, merely by know
ing the character of the past season, until some
law connecting these are worked out. This has
been demonstrated over and over again in diff
ferent parts of the world; but since, of course
people generally cannot keep posted in meteor
illogical literature, there will probably con-
tinue to appear such forecasts Of coming sea-
sons, based on apparent scientific conclusions.
Mr.. Clayton feels sure there is a law of recur-
renee of meteorological phenomena besides
the daily and annual periods and also that it is
not OF the character usually supposed and dis
cussed above.