In
the southern plain of this province, the distribution of mean annual
temperature is quite uniform oscillating between 24 and 26 o C (75
and 79 o F). In the winter, it can reach values ranging from 20
to 22o C (68 to 72 o F) and in the summer it rises from 26 to 28o
C (79 to 82 o F).
Annual rainfall can reach values between 1400 and 1800 mm (55 and
63 in) towards the north, in the surroundings of the Guaniguanico
mountain range, while more to the south it descends to values between
600 and 800 mm (24 and 31 in). Annual insolation, in terms of the
sum of hours of sunshine, is uniform and equals that of the sunniest
inland plains in the island reaching 2700 to 2900 hours of sunshine.
Along mountainous territories, the climate is varied, but dominated
by an average annual insolation going from the isohel of less than
7 hours of sunshine to that of 7.5 hours a day. Mean annual temperature
of the air is 24o C (75o F), with isolated isotherms of 23o C (73o
F) linking the highest places and the umbrageous caverns of the
hummocks' lowlands. During the first months of the year, in inner
mountain valleys, there have been notably low temperature records
little before sunrise when the thermometers of explorers have descended
from 4 to 6o C (39 to 43o F). Towards the western end of this region,
the absolute lowest annual air temperature isotherm, with a likeliness
of occurrence of a 5%, reaches 4o C (39o F ).
In general, the province's climate is a tropical rainy one. The
conditions of climate well-being are the best, especially in elevated
zones.