The Prachuap Khiri Khan climate is varied: In the north portion of the province, the climate is similar to that of Central Thailand. There is one main rainy season, an extended cool or dry season, and a short but hot summer; the southern portion of the province is comparable to Thailand’s tropical South.
The climate, weather and seasons of Prachuap Khiri Khan are primarily influenced by the two main climatic forces of Southeast Asia: the South Asian monsoon brings southwesterly winds and rain for about five to six months of the year, and the northeasterly or East Asian monsoon brings cooler northeasterly and relatively drier winds for about three-to four months.
There are three notable seasons in Prachuap Khiri Khan.
The period from about late November to February is the cool and arid season of Prachuap Khiri Khan, when precipitation is minimal. The prevailing northwesterly monsoon winds during these months are generally light, yet cool.
Occasional showers and thunderstorms – the remnants from dissipating sub-tropical systems in East Asia – are sporadic during this period, though typically, many weeks and months pass without a single drop of rain in central Prachuap Khiri Khan.
By about March to April a neutral monsoon spells flat wind and the warmest time of year for Prachuap Khiri Khan (and in Thailand overall)
By the end of April to May, Prachuap Khiri Khan’s rainy season commences with prevailing southwesterly winds bringing in the first of the year’s precipitation to the relief of municipalities gardens and plantations alike.
During this five to six month period, weather can be pleasant, though rain is not as incessant as its neighbors to the east and south; much of the Indian monsoon precipitation dissipates along the Tenasserim range naturally dividing the Isthmus of Kra.
By about the end of September, monsoon winds begin to shift again as the East Asian monsoon’s influence becomes dominant, bringing its cooler air and precipitation to kick off the cool season all over again.
October, which is at the climax of this shift – the battle of the continental monsoon gods – is historically Prachuap Khiri Khan’s wettest month.
When the East Asian monsoon ultimately prevails, rains subside and the cooler, dry weather returns to Prachuap Khiri Khan, “winter birds” from truly cooler geographies in the Northern hemisphere, and “summer birds” escaping the scorching zones in the Southern hemisphere flock to Thailand for the “high season ” of tourism.
The hottest temperature ever recorded in Prachuap Khiri Khan was 42 degrees, and the lowest was 6.4 degrees. Though the average high ranges between 30 (in January) to 34 degrees (in April), while the average low ranges between 20 to 24 degrees respectively.
According to 19 years of annual data from the Thailand Meteorological Department (2003–2021), Prachuap Khiri Khan receives on average about 1,073 millimeters of rain. The highest amount of annual rainfall recorded in Prachuap Khiri Khan was 429 millimeters, while the lowest was 226 millimeters.