When to visit
Although monsoon which is around June and July is not recommended for travelling by most travellers, it can actually be a great time to see the greenery around Bhutan's wildernesses. Since this is also the basic summer season, it offers vibrant green foresting and flourishing paddy fields against a backdrop of clear blue sky after the rain.
To avoid the crowd and catch the famous Black-Necked Cranes, winter would be the time to visit. To catch Himalayan blue sky without paying the additional tariff, consider visiting Bhutan in December. The temperature will not be too cold yet as lowest temperature usually takes places near the end of January.
Spring is the favourite time to visit Bhutan. Nature lovers who are keen on local flora should consider visiting Bhutan end of April or in May. Flowers would be on full bloom then. Fall is another high and crowded season for Bhutan. Though Bhutan does not offer browning forest or maples, the mild weather in autumn makes it a perfect time to visit Bhutan. Thimphu Festival usually takes places at the end of September or early October
The southern part of Bhutan is tropical, and in general the eastern region of the country is warmer than the central valleys. However, the higher the altitude, the cooler the weather, and with a brisk wind blowing down off the mountains even low-lying valleys can become chilly. The best time to visit Bhutan is from October to May when the climate is mainly dry and sunny, while in December and January snow may block mountain passes and travel is therefore restricted to the western valleys.