Which regions of Paraguay have the least amount of drought and abundant annual rainfall historically?
Executive summary
The wettest, least drought-prone parts of Paraguay are in the east and southeast — the Paraná/Paraneña lowlands, Paraná Plateau and the Alto Paraná basin — where mean annual precipitation commonly ranges from about 1,500 mm up to roughly 1,800–2,000 mm in the rainiest spots, making these regions historically abundant in rainfall [1] [2] [3]. By contrast, the Gran Chaco and western/central Chaco plains are the driest and most drought-prone, with long-term annual totals typically between roughly 400–800 mm (often cited near 600–800 mm and occasionally 400–700 mm), and they suffer most during La Niña-related drought episodes [4] [1] [3].
1. Where the rain falls: eastern Paraguay’s high-precipitation belt
Eastern Paraguay — encompassing the Paraná River corridor, the Paraná Plateau and the Alto Paraná basin — is consistently identified in climatological sources as the country’s rainiest sector, with mean annual rainfall commonly reported between 1,500 and 1,800 mm and local measurements and datasets pointing toward values approaching 2,000 mm in some areas such as Ciudad del Este and forested highlands [1] [5] [6]. International climate portals and UN analyses emphasize that the southeast’s temperate, humid and forested landscapes receive substantially more precipitation than the rest of the country, and that these higher totals translate into lower historical drought incidence but higher flood risk during anomalously wet ENSO/El Niño years [7] [2] [8].
2. The Gran Chaco: Paraguay’s drought-prone west
The Gran Chaco and western Paraguay are repeatedly described as semi-arid to hot semi-arid, with much lower average precipitation — commonly cited around 600–800 mm and in some climatologies 400–700 mm per year — making this the region most susceptible to drought, heat waves and water stress; official and academic profiles single out Central Chaco, Pilcomayo areas and districts like Mariscal Estigarribia as recurrent drought hotspots [4] [1] [3]. Reports also link the Chaco’s vulnerability to recurring La Niña cycles and note that droughts there have serious consequences for agriculture, hydropower and indigenous and rural communities [4] [1].
3. Middle ground: central and Asunción-area rainfall variability
Central Paraguay, including the Asunción metropolitan area and surrounding Paraneña lowlands, sits between the extremes: long-term averages are often near 1,000–1,300 mm annually, but interannual variability is substantial — station records for Asunción show extremes from under 800 mm to well above 1,500 mm in different years — so the area experiences both relative rainfall abundance and episodic dry spells depending on ENSO and seasonal shifts [9] [10] [11]. That variability explains why central Paraguay can be both agriculturally productive and vulnerable to alternating flood and drought impacts documented in national case studies [8] [12].
4. Climate drivers and how they shape geographic risk
ENSO (El Niño/La Niña) is a dominant driver of Paraguay’s interannual wet–dry swings: El Niño years tend to bring above-average rainfall and floods especially to the eastern basins, while La Niña enhances drought frequency/intensity in the west and across certain agricultural zones, explaining the geographic pattern of fewer droughts in the southeast and more frequent droughts in the Chaco [4] [1] [13]. Sources flag that local topography (plateaus and river basins), land cover and river systems also amplify differences: the Alto Paraná/Paraná Plateau channels moisture and sustains humid forests, while the flat, xeric Chaco lacks barriers that could enhance rainfall development [6] [2].
5. Caveats, competing emphases and data limits
While multiple authoritative sources converge on east = wet, west = dry, exact rainfall numbers vary among datasets and station records: some portals report mean annual totals for the eastern lowlands near 1,600–1,800 mm and for the Chaco near 400–700 mm, while city-based records for Asunción and Puerto Bertoni show wide year-to-year swings, highlighting limits in using point stations to represent broad regions [4] [9] [1]. The reporting reviewed does not provide a single harmonized, high-resolution map in this packet, so finer spatial delineation (for example sub-regional pockets within the Paraneña or northern Chaco) would require direct interrogation of the World Bank climatology grids or national meteorological archives referenced in the Climate Change Knowledge Portal [12] [7].