The times dispatch. [volume] (Richmond, Va.) 1903-1914, 1908-07-01
looping WEATHER
TO FIND COMFORT
Director Evans Explains Method
OF Estimating Possible July
Record.
EXPECT FEW 99-D EG Rec DAYS
Mercury May Reach 90 Degrees
on Not Less Than Five OF Not
More Than Seventeen Days.

[ t43l 4
when a record OF observations OF
weather conditions has been made Cor
a period Of years" said Section Direc-
tor Evans yesterday, "the averaging
OF any of its parts for the entire
period-as temperature, for instance
results in a normal for that part
Thus, II twenty years observations
were available, and it was desired to
ascertain the normal temperature for
July. the average for the twenty Julys
recorded would give It The value OF
such q normal depends. Of course, on
the number of years record used in
obtaining It, so that the greater the
period the better the normal. In this
way the occasional departures from
true normal. due to excessively hot or
cold, wet or dry weather, are smoothed
down through long series OF years,
and practically eliminated
Possibility OF Hot Days.
However undesirable periods OF UNI
seasonable weather may be when
viewed from the standpoint Of personal
comfort. they are. nevertheless, very
useful in determining the Limitations
of the climate of place.
ITO illustrate, II, during the hottest
July on record at Richmond the high
est temperature reached was 90 de-
grees, 1t would be reasonable to as
sumo that the curt<nt July would not
surpass it. Similarly the probabilities
as to the lowest temperature and the
greatest and least rainfall the currEnt
July would be arrived at.
by this means one could, II de-
sired, formulate scheme OF weather
expectancy for any month, and such
scheme for July would be expressed
somewhat as follows
The mean temperature Will probably
not be lower than II degrees nor high
er than 81 degrees, while the highest
and the lowest tempera lures that will
be reached are not likely to- exceed 80
degrees and 81 degrees. respectively
There will be not less than five days
with maximum temperature Of 90.
or more degrees. Probably the num-
Der will exceed five. but 1t will not
be more than seventeen.
Precipitation for July.
"The monthly rainfall will probably
range between three inches and six and
Inches. The heaviest rain
fall on any one day will not exceed
three and one-half inches, and rain
may be expected to fall on about thir-
tSUh udS IA LIS llloliItl. WIN respect
to sunshine. there will be an average
Of about 6S per cent. of the possible
amount, while thunderstorms are like
~ to occur on not less than four nor
more than thirteen days. Seventy
eight per cent. of humidity should pre-
vail during the morning hours of the
month. OF clear days there will be
about eleven; Of partly cloudy. four
teen. and Of cloudy. six. The winds
will be mostly from the south. and 1t
Is not probable that they will at any
time exceed rate of forty-five miles
per hour
while it will be at once observed
that such statement Of weather ex-
pectancy lacks definiteness. and is.
therefore. largely bereft of any prac-
teal value, 1t will, when based on
data covering a long period Of years.
represent reasonable probability. and
will verify approximately, unless the
month is an abnormal one"