Normal to below normal rainfall forecast for southwest monsoon in South Asia

Normal to below normal rainfall is likely during the 2023 southwest monsoon season (June – September) over most parts of the South Asia, according to the WMO-backed South Asian Climate Outlook Forum (SASCOF).  

From June through September, the southwest monsoon dominates life in much of South Asia and has an all-pervading influence on the socio-economic fabric of the region and thus of national economies. It accounts for 70-80 per cent of the annual rainfall in most parts of the region (excepting Sri Lanka and southeastern India), which is home to about one fourth of the world’s population.

Variability of monsoon rainfall, both in amount and distribution, often results in severe droughts or floods, with large-scale impacts in terms of agricultural production and food security. In the interests of sustainable economic growth, South Asia requires even more accurate, reliable and useful information about the monsoon.

Improved early warnings about monsoon activity support the UN Early Warnings for All Initiative.

Below normal rainfall is likely over some areas in northwest, central and north-eastern parts of the region while above normal rainfall is likely over far northern and northwest parts of the region as well as parts of eastern and southern regions of South Asia, according to the outlook issued at the 25th session of SASCOF.

Above normal minimum and maximum temperatures are likely over most parts of South Asia, with the exceptions being, respectively, parts of the foothills of Himalaya, and central and parts of the southern region.

El Niño

The climate outlook was collaboratively developed by all nine National Meteorological and Hydrological Services (NMHSs) of South Asia with the support from WMO Regional Climate Centre Pune hosted by India Meteorological Department, Regional Integrated Multi-hazard Early Warning System (RIMES), other global and regional partners and international experts.

It is based on expert assessment of the prevailing global climate conditions and forecasts from different models from around the world.

The multi-year La Niña has ended around March 2023 and there are currently ENSO-neutral conditions over the tropical Pacific Ocean. El Niño conditions are likely to develop during the southwest monsoon season, according to the latest WMO Update. However, there is uncertainty in its strength and the time of its onset. El Nino conditions are typically associated with normal to below normal southwest monsoon rainfall over most part of South Asia but it is also recognized that other regional and global factors as well as the intra-seasonal features of the region can also affect the seasonal climate patterns over the region.

SASCOF was launched in 2010 under the auspices of WMO to engage South Asian countries that share a strong and common interest in understanding and forecasting the monsoon. It is one of a worldwide network of Regional Climate Outlook Forums sponsored by WMO and its partners to promote collaboration and information sharing on seasonal climate prediction and related issues.