The climate in Bhutan is extremely varied, depending on vast differences in altitude and the influence of the north Indian monsoon. Subtropical in the south to temperate in the highlands and polar-type climate, with year-round snow in the north.
Bhutan experiences five distinct seasons: summer, monsoon, autumn, winter and spring.Western Bhutan has the heavier monsoon rains; southern Bhutan has hot humid summers and cool winters; central and eastern Bhutan is temperate and drier than the west with warm summers and cool winters.
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.
There are two main seasons for visiting Bhutan, spring (March to May) and autumn (September to November), both of which offer the chance to visit festivals and to trek. Autumn is the traditional high season in Bhutan. September and October have the highest number of tshechus (religious festivals). Trekkers particularly enjoy the clear view of the mountains in October and low rainfall. Rice harvest means a picturesque landscape remarkable terraces and changing color.
Spring is the season for wonderful flowers and birds, the days are warm and the mountains peaks are still visible for most of the time.
Average Temperatures in Bhutan based on Maximum and Minimum day/night (Celsius)
| Paro | Thimphu | Punakha | Trongsa | Jakar | Mongar | Trashigang | |
| Jan | 9.4 -5.8 |
12.3 -2.6 |
17 4.3 |
13.0 -0.2 |
10.8 -5.1 |
15.5 8.2 |
20.4 10.5 |
| Feb | 13 1.5 |
14.4 0.6 |
19 7.8 |
13.9 0.4 |
10 -1.4 |
15.9 8.3 |
21.7 11.5 |
| Mar | 14.5 0.6 |
16.4 3.9 |
22.8 10.4 |
16.7 4.4 |
16.2 3.5 |
20 11.6 |
24.8 14.4 |
| Apr | 17.6 4.6 |
20 7.1 |
26.2 12.9 |
20.1 6.6 |
18.7 3.9 |
22.8 14 |
28.3 17 |
| May | 23.5 10.6 |
22.5 13.1 |
29.1 17.7 |
21 11.6 |
21.3 9.5 |
25.1 17.4 |
302 2.6 |
| June | 25.4 14.1 |
24.4 15.2 |
29.2 20.1 |
22.2 13.6 |
22.5 13.5 |
26.1 19.5 |
30.7 22.6 |
| July | 26.8 14.9 |
25.9 15.6 |
30.4 20.5 |
25.3 15.3 |
24.1 13.6 |
27.1 19.8 |
31.5 23.1 |
| Aug | 25.3 14.7 |
25 15.8 |
29.1 20 |
23.8 15 |
231 3.7 |
25.4 19.6 |
30.2 22.7 |
| Sep | 23.4 11.7 |
23.1 15 |
27.5 19.1 |
22.6 14.2 |
21.6 12.1 |
24.7 19.4 |
30 21.9 |
| Oct | 18.7 7.4 |
21.9 10.4 |
26.1 14.7 |
21.8 11.7 |
19.5 5.9 |
22.7 15.8 |
29.1 17.7 |
| Nov | 13.9 1.4 |
17.9 5 |
22.6 9.6 |
19.8 6.4 |
16.1 -0.5 |
19.9 11.2 |
26.1 13.6 |
| Dec | 11.2 -1.7 |
14.5 -1.1 |
19.1 6.3 |
18.2 2.5 |
12.3 -2.3 |
17.7 9.5 |
23 11.6 |
