The country received a slightly below-normal rainfall compared to the long-term average, last year. According to the National Centre for Hydrology and Meteorology or NCHM’s State of Climate Report 2023, the annual average rainfall was almost 1,800 millimetres in 2023. Rainfall is measured in millimetres to provide a standardised and uniform way to quantify it. The NCHM uses 20 meteorological stations across the country to collect rainfall data.
Compared to the quantity of rainfall in 2022, the country received around 212 millimetres or eight inches less rainfall in 2023.
The annual average rainfall in 2022 was a little over 2,000 millimetres. In 2022, the country received near-normal to slightly below-normal rainfall.
Summer monsoon, a seasonal wind pattern that brings heavy rainfall, recorded the highest rainfall received last year as compared to other seasons. Bhutan experiences summer monsoon from June to September.
However, as per the State of Climate Report, last year’s summer monsoon rains were comparatively less as compared to average rainfall between 1996 and 2022.
Among the 20 districts, Gasa is the wettest with the district seeing rainfall in 200 of the 365 days last year.
However, in terms of sheer volume, Phuentshogling has the highest total annual rainfall at over 6,500 millimetres, which is over three times the national average.
Samtenling in Sarpang and Tashichhoeling in Samtse recorded an average annual rainfall of almost 5,500 millimetres.
With rainfall declining, the average annual river flow of 2023 also saw a decline across all the major river basins of Wangchhu, Punatsangchhu, Chamkharchhu, Kholongchhu, Kurichhu, and Drangmechhu.
The report compared 2023 river flow data with historical data recorded between 1992 and 2022.
Samten Dolkar
Edited by Sherub Dorji
