Climate And Weather
The climate in Bhutan is extremely varied. This variation in the climatic conditions and average temperature can be attributed to two main factors-the vast differences in altitude present in the country and the influence of North Indian monsoons.
Southern Bhutan has a hot and humid subtropical climate that is fairly unchanging throughout the year. Temperatures can vary between 15-30 degrees Celsius (59- 86 degrees Fahrenheit). In the Central parts of the country which consists of temperate and deciduous forests, the climate is more seasonal with warm summers and cool and dry winters. In the far Northern reaches of the kingdom, the weather is much colder during winter. Mountain peaks are perpetually covered in snow and lower parts are still cool in summer owing to the high altitude terrain.
The Indian summer monsoon begin from late-June through to late-September and is mostly confined to the southern border region of Bhutan and it brings heavy rain and high humidity. These rains bring between 60 and 90 percent of the western region’s rainfall.
Annual precipitation ranges widely in various parts of the country. In the Northern border towards Tibet, the region gets about forty millimeters of precipitation a year which is primarily snow. In the temperate central regions, a yearly average of around 1,000 millimeters is more common, and 7,800 millimeters per year has been registered at some locations in the humid, subtropical south, ensuring the thick tropical forest, or savanna.
Thimphu experiences dry winter months (December through February) and almost no precipitation until March, when rainfall averages 20 millimeters a month and increases steadily thereafter to a high of 220 millimeters in August for a total annual rainfall of nearly 650 millimeters.
Bhutan’s generally dry spring starts in early March and lasts until mid-April. Summer weather commences in mid-April with occasional showers and continues to late June. The heavier summer rains last from late June through late September which are more monsoonal along the southwest border.
Autumn, from late September or early October to late November, follows the rainy season. It is characterized by bright, sunny days and some early snowfalls at higher elevations.
From late November until March, winter sets in, with frost throughout much of the country and snowfall common above elevations of 3,000 meters. The winter northeast monsoon brings gale-force winds at the highest altitudes through high mountain passes, giving Bhutan its name – Drukyul, which means Land of the Thunder Dragon in Dzongkha (the native language).
Average Temperatures in Bhutan
It should be noted that average temperatures are recorded from valley floors. There can be considerable divergences from the recorded figures depending upon elevation.
It start from the March to June, the southern regions experience typical sub tropical weather like hot and humid conditions. Whereas in Thimphu, Paro, Bumthang valley has warmer days with cool night and clear blue sky. It is noticeably warmer in Punakha & Wangdi valley. This periods also offers time windows to do high altitude trek like Jhomolari, Dagala, Druk path etc. Rhododendron and wild flowers blooms surrounds the trails whilst trekking especially at higher elevation. And also most likely to see the wild life as well, they comes out from hibernation after cold, long unforgiving winter.
Beginning of July marks the advent of south east monsoon till the earlier September. Bringing much relieve after scorching summer heat in southern belt. And a boon to farmers for the cultivation of their seasonal crop mainly Rice. The rain in the valleys like Thimphu, Paro Punakha etc is relatively far less in proportion in comparison with southern belt. Southern regions are in first range to confront moisture laden south east monsoon so i it shed bulk of its moisture in these regions. And also the valley in west and central Bhutan fall under leeward or rain shadow side, which makes the rain reach in fairly less proportion. It carpets the valley and surrounding vegetation with greenery.This period bring the trekking into complete standstill as the trails get wet, slippery and muddy.
It normally start from tail end of September till November, when the weather tend to slowly stabilise after the monsoon. The sky start to get more clearer with warm autumn sun and continues offering spectacular view of far off peaks.
These months are considered as the best time for Trekking, these periods make conditions favourable for trekking with accessible high passes and stable temperature. it throws open small windows of time in a year, specifically, for the epic Snowman trek. As for other high altitude trek like Dagala, Jhomolari, Druk Path it is best time as well.
It starts from December till February. Specifically, it’s the time of year when night tend to get cold with day being warm with bright sun. Blue winter skies serve a striking background to the snow-capped peaks., however, the higher passes like Dochula, Pele La, Chele La experience snow but the valleys remain bereft of heavy snow with occasional light dusting of it . The possibilities of heavy snow remain only if there is sudden and dramatic change in temperature.
Higher passes remain closed due to snow so high altitude trek becomes distance dream during winter, however weather in lower altitude places like Punakha experiences pleasant climate. It becomes favourable time to do low altitude winter trek like Samtegang and Nabji Korphu.