Residents and visitors in Bhutan should prepare for a winter that promises warmer daytime temperatures and near-average rainfall, though conditions may bring extended dry spells. The National Centre for Hydrology and Meteorology (NCHM) released its Winter Monsoon Rainfall and Temperature Forecast for December 2024 to January 2025, painting a picture of a season that deviates from past chilly and snow-laden winters.
According to the NCHM forecast, daytime temperatures are expected to exceed the historical “normal,” making for a warmer winter overall. However, the nights should remain typical of the season, with minimum temperatures aligning closely with what has been observed over the years. The precipitation is projected to hover around normal levels, based on data collected from 1996 through 2023. In the forecasting model, even slight deviations of 10 percent from these historical averages determine whether conditions are classified as “slightly above normal” or “slightly below normal.”
Diverse Data Sources Enhance Accuracy
The seasonal forecast is the culmination of an extensive analysis that pulls from both local and international data reservoirs. Bhutan’s national meteorologists, in collaboration with global agencies such as the World Meteorological Organization and the South Asian Climate Outlook Forum (SASCOF), have incorporated predictions from regional institutions like the International Research Institute for Climate and Society (IRI), Copernicus Climate Change Service (C3S), and the Japan Meteorological Agency (JMA). This blend of perspectives has led to a somewhat mixed picture: while four agencies point towards below-normal precipitation, five others predict above-normal temperatures for the upcoming winter months.
Meteorologists also factored in significant global climate drivers such as El Niño and the Indian Ocean Dipole. “Such elements influence weather patterns, including the monsoon, which in turn can affect our winter conditions,” an NCHM representative explained.
Westerlies and Western Disturbances: A Recipe for Snowfall
The forecast underscores the influential role of the westerlies—dry winds blowing from the west—which typically lead to lower temperatures at higher elevations. While these winds can usher in snowfall when they interact with Western disturbances, snowfall predictions remain challenging due to the interplay of several weather factors such as moisture availability, wind conditions, and sub-zero temperatures.
Indeed, following an NCHM forecast issued on January 6, snowfall was recorded across high-altitude regions, particularly in mountain passes and areas of western, central, and northern Bhutan. Regions like Gasa and Jabana in Paro experienced significant snow from the evening of January 7. However, an official from NCHM cautioned that it is difficult to predict exactly how much snow will fall during the winter season. “Snow formation depends on a delicate balance of factors, and while our models provide valuable insights, the actual snowfall can vary,” the official stated.
The Importance of Snowfall in a Changing Climate
Snowfall in Bhutan holds considerable environmental significance. Aside from its aesthetic appeal, the winter snow is crucial in recharging groundwater supplies, maintaining river flows, and supporting agriculture. However, many local observers have noted that winters in Bhutan seem to be getting drier over time, with less snowfall than in previous decades. The NCHM emphasized that a comprehensive evaluation of climate change impacts on snow coverage would require at least 30 years of detailed climatological data—a milestone they hope to achieve with continued annual updates.
As Bhutan stands on the precipice of a warmer winter, local communities are keeping a keen eye on meteorological updates. The diverse data sources and thorough analysis behind this forecast underscore the complexity of climate dynamics in the region. Whether the coming winter will mark a new normal for the Himalayan kingdom remains to be seen, but for now, the emphasis remains on preparation and adaptation to a changing climate.
