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.
