Droughts occur most frequently in subtropical regions near 30 degrees latitude, the Mediterranean basin, sub-Saharan Africa, the Horn of Africa, Australia, the American Southwest, and parts of South and Central Asia. These areas share a combination of atmospheric patterns, ocean influences, and geography that make prolonged dry spells a recurring feature of life. As of 2022-2023, roughly 1.8 billion people were living under active drought conditions worldwide.
Why Certain Latitudes Stay Dry
The single biggest factor determining where droughts concentrate is a global atmospheric engine called the Hadley circulation. Air heated at the equator rises, moves toward the poles, then sinks back down at roughly 30 degrees north and south latitude. That sinking air compresses and warms, suppressing cloud formation and rainfall. The result is a belt of semiarid and arid land circling the globe at those latitudes: the Sahara, the Arabian Peninsula, northern Mexico, the Australian Outback, and the Kalahari Desert all sit squarely in this zone.
Regions just outside these belts are especially vulnerable. They receive enough rain in good years to support agriculture and large populations, but small shifts in atmospheric circulation can tip them into severe drought. The Sahel, southern Spain, and the American Southwest all fit this profile.
Sub-Saharan Africa and the Sahel
The Sahel, the wide band of semi-arid land stretching from Senegal to Sudan between the Sahara and the tropical forests to the south, is one of the most drought-prone regions on Earth. Rainfall there depends on how far north the tropical rain belt pushes each summer. That position is sensitive to ocean temperatures: when the Southern Hemisphere’s oceans are relatively warm compared to the Northern Hemisphere’s, the rain belt gets pulled southward and the Sahel dries out. Scientists identified this mechanism while studying the devastating Sahel droughts of the late 20th century, and increasing industrial pollution in the Northern Hemisphere may have contributed by cooling that hemisphere’s oceans relative to the south.
East Africa, including Somalia, Ethiopia, and Kenya, faces a different but equally punishing pattern. The Horn of Africa depends on two short rainy seasons, and the failure of even one can trigger crisis. Most of Africa was in some degree of drought or abnormal dryness at longer timescales as of early 2024, with conditions especially severe along the Mediterranean coast, across southern Africa, and in parts of the east. In West Africa, hot and dry conditions in recent years have damaged cocoa harvests in Ghana and Ivory Coast, which together produce nearly 60% of the world’s cocoa.
The Mediterranean Basin
Southern Europe and North Africa are experiencing a sharp increase in drought severity. Southern Italy, southern Spain, Malta, Morocco, Algeria, and Tunisia have all faced severe conditions driven by prolonged above-average temperatures, warm spells, and poor precipitation. Northern Africa has endured recurring drought for the past six years, while Europe has dealt with more than two years of persistent dryness. At longer timescales (three to six years), dry conditions stretch from southern Europe deep into north-central Europe.
Climate projections strongly agree that droughts in the Mediterranean will become more frequent and more intense. The region’s soils are shallow and highly susceptible to degradation, and countries along the southern and eastern shores that rely on rain-fed agriculture are especially exposed. North African and Middle Eastern nations already see their crop yields swing dramatically from year to year based on rainfall variability alone. Unsustainable land use is compounding the pressure, though the full extent of soil degradation across the region remains unknown.
The American Southwest
The western United States has been locked in a megadrought since 2000, the most significant prolonged dry period in the region in centuries. As of 2025, 100% of the Colorado River Basin is in drought, with large areas classified at extreme or exceptional levels in the Upper Basin, where most of the river’s water originates. The basin spans all of Arizona and parts of Colorado, California, Wyoming, Utah, New Mexico, and Nevada.
The consequences are visible in the region’s reservoirs. Between 2002 and 2024, the Colorado River Basin lost about 27.8 million acre-feet of groundwater, roughly equal to the entire storage capacity of Lake Mead. Water levels in Lake Powell could fall low enough to stop hydroelectric generation by late 2026. Utah’s reservoirs have been drawn down at more than double the normal rate. Even Southern California, despite two good winters that filled most of the state’s reservoirs, remains in moderate to extreme drought with impacts on agriculture, public health, and fire risk.
Northern Mexico and parts of the southern U.S. Plains through the Midwest also show persistent dryness at longer timescales.
Australia and Southeast Asia
Australia’s interior is arid by default, but the continent’s drought cycle is heavily amplified by a climate pattern in the Pacific Ocean. During El Niño events, when sea surface temperatures in the central and eastern Pacific rise, rainfall decreases sharply across Australia and Southeast Asia. These events can push already dry conditions into severe agricultural and water-supply crises. During the opposite phase, La Niña, Australia typically receives more rain, but parts of southern Brazil, northern Argentina, and the southern United States tend to dry out instead.
This seesaw means drought risk is never static. El Niño pushes drought toward Australia, Southeast Asia, South Africa, and northern South America. La Niña shifts it toward the southern U.S., northern Mexico, eastern Europe, and western Russia. The southern U.S. and northern Mexico corridor stands out as one of the areas most consistently affected across both phases.
Central and South Asia
Afghanistan is currently in what is considered its worst drought in 30 years, with warmer-than-average winters and far below-normal mountain snowpack raising fears of continued water shortages. Southwest Asia more broadly shows persistent dryness at longer timescales. Northern China, Mongolia, and much of the Brahmaputra River Basin in southern Asia also register prolonged dry conditions spanning two to six years.
These regions depend heavily on snowmelt and seasonal monsoons. When either falls short, the effects cascade quickly through agriculture and drinking water supplies.
South America
Brazil ranked 2023 as its second-driest and second-hottest year on record. Western Brazil and Venezuela have experienced persistent dryness, and the southern tip of the continent has also been affected. At longer timescales, virtually the entire South American continent shows some degree of drought or dryness. El Niño and La Niña both influence the continent, with La Niña tending to dry out northern Argentina and southern Brazil between November and January.
Four Types of Drought
Not all droughts look the same, and understanding the type helps explain why some regions suffer more than rainfall numbers alone would suggest.
- Meteorological drought is simply a sustained shortfall in precipitation. This is the starting point for all other types.
- Agricultural drought occurs when soil moisture drops low enough to damage or kill crops. It can develop quickly in hot regions even with moderate rain deficits, because high temperatures pull moisture from the soil faster.
- Hydrological drought means rivers, lakes, reservoirs, and underground water supplies have fallen below normal. This type lags behind the others and can persist long after rain returns, as the American Southwest’s depleted reservoirs demonstrate.
- Socioeconomic drought happens when dry conditions disrupt the supply of water-dependent goods, from food to electricity. Cocoa shortages from West African drought and threatened hydropower at Lake Powell are both examples.
A region can experience all four simultaneously. The most vulnerable places, including the Sahel, the Mediterranean, and the Colorado River Basin, frequently do.