Paraguay experiences a subtropical to temperate climate with southern hemispheric seasons characterized by wet summers between December and January and dry winters from June through August. The mean annual temperature is 23.5°C with geographical variation between the warmer western regions and cooler eastern regions of the country. The historical average precipitation is 1,087.1mm concentrated in the south-eastern regions. The Paraguayan Chaco in the North and western regions is 25% of the Gran South American Chaco, considered the second largest forest ecosystem in the continent. The Eastern regions are home to humid forests of Bosque Atlántico del Paraná, pasture land, savannas and dry forests in Cerrados, and grassland and wetlands of Pastizales de la Mesopotamia near the Argentinean border. El Niño Southern Oscillation influences inter-annual weather patterns in the country. El Niño years are associated with anomalous precipitation in mid spring and autumn and humid summers that are particularly pronounced in the east and lower Chaco. Paraguay also experiences occasional heat waves in the summer, frosts in the winter, and flooding events associated with El Niño (NDC, 2015). Key historical climate trends are summarized below:
- The temperature of the coldest month has increased in recent years to 18.37°C in 1991-2016 from 18.13°C in 1901-1930.
- Average annual temperatures have been steadily increasing over the past century, with highest increase during southern hemispheric spring and winter months.
- Historically the southeastern valleys and plateaus experience more temperate and humid climates compared to warmer temperatures in the Chaco region in the North West.
- Average annual precipitation reflects high oscillations from year to year with extreme reductions in precipitation in 1999-2000 and precipitation above the 99th percentile in 1982-1983 (NDC, 2015).
- Precipitation is concentrated in the southeastern region of Paraguay and lower in the northwestern regions of the country.
- The average precipitation during the wet southern hemispheric summer increased in recent years (1991-2016) with four months surpassing 120mm/month, compared to zero months surpassing 120mm/month in 1901-1930.
- Precipitation during traditionally dry southern hemispheric winters is not significantly different in recent years (1991-2016) compared to 1901-1930.
This section provides the options to visualize historical climate data for different timeframes via map and annual cycle chart.