'IRAQ AND THE PERSIAN GULF' [‎127r] (258/862)

CLIMATE
173
minimum is 12 0 (3 Jan. 1925). There is little doubt that the south is
considerably warmer in winter than the north or west, and at Shuaiba
there is only one official reading below 20°.
Many winter days are warm, and this warmth by day emphasizes
the cold by night. The day temperature at Shuaiba has reached 88° in
December, 8i° in January, and 85° in February. Mosul has, however,
not recorded more than 66° in January and this is exceptional. It
is known that lower temperatures than those at Mosul occur in
Kurdistan, but there are no official figures.
The difference between the mean monthly maxima and the mean
monthly minima at Shuaiba varies between 40° and 55 0 , being
highest in the transitional seasons of spring and autumn. Probably
the difference is much the same elsewhere. Exceptionally the night
temperature has fallen 6o° below that of the preceding day tempera
ture. The fall in temperature is very rapid after sundown, and
chills are easy to catch unless precautions are taken.
The suddenness of change from summer to winter and vice versa
has been mentioned above. Normally winter comes in November, but
occasionally the heat lasts into that month. At Hinaidi the mean
daily maximum in November is 76°, but exceptionally the day tem
perature reaches 90°, though frost at night has also been known there
in the same month. During the War of 1914-1918 tents were re
quired by the fighting troops to keep out the cold and wet in winter
and to ward off the sun in summer; in November they were required
for both purposes; but single-fly tents, though better than nothing,
are little use for either. In the great heat of early July 1916 in front
of Kut the temperature recorded in a double-fly tent was about
5 0 above the official maximum shade temperature (128°) at Army
headquarters, and that in a single-fly tent on the opposite side of the
Tigris, and inland from the river, 8° to 9 0 higher (i4 l0 )*
Humidity (Tables III, IV)
Relative humidity is low in summer and high in winter, and higher
in the early morning than later in the day. This is a natural con
sequence of the great ranges of temperature, and it applies to all
the five stations in different degrees. Unfortunately the mean
figures for the month do not tell the whole story, and there are neither
sufficient stations nor altogether suitable statistics available to deal
fully with the physiological effects of humidity.