For years, Sudanese people have come to anticipate the stock excuse from officials, “the rains surprised us”, a line that turned into a popular joke after it was repeated to justify federal and state failures to prepare for the rainy season and its attendant disasters, even though the season is known to start in June and end in late September.
As climate change intensifies worldwide and across the Horn of Africa, particularly in Sudan, temperatures are rising and rainfall patterns are becoming increasingly erratic. The autumn rains have become a looming menace for the entire region, which already suffers from fragile governance, decaying infrastructure, and mounting armed conflict and communal fighting. In recent years, weather extremes, particularly heavy rainfall, have become more severe, triggering floods and landslides that in turn inflict massive damage on communities and agricultural projects, followed by cascading health, economic, and security consequences.
Half the season: A delayed flood
In its first half, before Aug. 15, the current June–September 2025 rainy season did not exhibit extreme rainfall patterns. According to the IGAD Climate Prediction and Applications Centre (ICPAC), July saw lower average rainfall than in recent past years; however, early August brought heavy rain over the Atbara River basin that will inevitably boost the river’s streamflow, while the Blue Nile basin remained drier than usual.
Half the season passed quietly—until sudden downpours tipped the balance.
This matches ICPAC’s earlier outlook from May, which warned the season could arrive slightly late, a signal reinforced by July’s subdued rainfall. The center also put the probability that seasonal rainfall would exceed the long-term average at 55 percent, basing its forecast on six global climate models. Crucially, the recent uptick over the Atbara basin suggests the “other-half-of-the-season” scenario is no longer far-fetched, and may be very near, especially in light of IGAD’s projections and the Sudan Meteorological Authority’s orange alert on social media warning of a high-risk window for heavy rain and thunderstorms in Blue Nile State, eastern Sennar, western West Kordofan, and the southern and western reaches of North Darfur.
It is well known that the Ethiopian Highlands play a central role in forming rain clouds over eastern, southeastern, and central Sudan, and that they supply the Nile’s waters. The key driver in this chain is the Indian Ocean: as sea-surface temperatures rise over that vast basin, rainfall increases over the highlands. Moist monsoon winds blow from the Indian Ocean toward Ethiopia’s escarpments, which act as a barrier and force the air upward; mountains push the moist air into colder upper layers where the vapor condenses into rain-bearing clouds. Oceans are therefore the primary regulator of global temperatures, covering more than 70 percent of the planet. And because Sudan sits on the continent’s eastern side, not far from the Indian Ocean, it is indirectly affected by shifts in the ocean’s temperature, whether toward wetter seasons or drought.
Sudan’s dam authorities typically begin impoundment around mid-August, in coordination with Ethiopian counterparts, for technical reasons tied to dam efficiency and silt loads. That schedule is also a proxy for August being the rainiest month. Most of Sudan’s historic floods have struck in August and September. One enduring memory is the 1988 flood, when some 200 millimeters fell on Khartoum in just 24 hours, about 80 percent of the city’s annual average.
Landslides in Darfur
Dark green indicates areas that experienced anomalies, deviating from rainfall averages during the middle of last August, which resulted in heavy rain across parts of eastern Sudan, River Nile State, and the southern states, as well as the Darfur states.
The data indicate vast stretches of Darfur already saw very high rainfall over broad areas. Totals exceeded 200 millimeters, the same order as the amount that fell on Khartoum during the 1988 flood. A “200 millimeter” reading is a depth: if that rain collected on a flat, impermeable surface, it would form a 20-centimeter layer of water. Each millimeter equals one liter per square meter; 200 millimeters equal 200 liters per square meter. That is immense if it falls in a single day, and prolonged seven-day totals magnify the damage dramatically.
While such water can be a boon for planting, easing hardship for residents, the surge also threatens destructive flash floods. That is exactly what happened on Aug. 31, after heavy August rains drenched the Jabal Marra range. The soil became waterlogged, its mass increased, and pressure on the underlying rock rose, forcing movement. Combined with the area’s steep slopes, the mass shift triggered a landslide that struck the village of Tarsin. Reports on the human toll and livestock losses remain conflicting.
The fact that these natural disasters are occurring in Darfur, already gripped by bloody conflicts and acute humanitarian crises, and home to hundreds of thousands of displaced people, portends severe deterioration in public health and security. Access to services and aid is already difficult, and supply chains are disrupted, especially in besieged places such as Al-Fashir or at crossings along the Sudan–Chad frontier.
A land at the mercy of climate change
Sudan has endured both floods and droughts—extremes that uproot lives, reshape politics, and fuel conflict.
Modern Sudan has moved between environmental extremes, years of heavy rains and prolonged droughts, each with devastating ecological and economic impacts, plus demographic, social, and security fallout that reverberates into politics. The 1946 flood left a deep imprint in modern memory, the highest in the records, with rainfall reaching 338.85 millimeters while the known national annual average was under 257.17 millimeters. By contrast, the years 1979–86 were marked with extended drought, peaking in 1984 when the national annual total fell to just 128.25 millimeters, driving large waves of displacement across the Horn and within Sudan.
Even so, the variance in Sudan’s average rainfall has been relatively modest overall. Crucially, those totals are not evenly distributed across the country. Most rain falls in Blue Nile, Sennar, and Kordofan; Al-Jazirah and Khartoum sit in the middle; rainfall is relatively low in River Nile State; and it is nearly absent in the Northern State, apart from occasional anomalies associated with extreme events such as El Niño.
By regional standards, Sudan is comparatively well-endowed with rainfall, particularly in its southeastern, southern, central, and western regions. Water abundance influences regional conflict dynamics and interventions, including debates over the Grand Ethiopian Renaissance Dam and Nile allocations. Egypt argues that Ethiopia and Sudan have multiple water sources, rain and groundwater, whereas Egypt receives very little rain.
| Country | Average annual rainfall (mm) | Average annual rainfall (billion cubic meters) |
| Sudan | 257 | 440 |
| Egypt | 18 | 1.3 |
| Ethiopia | 848 | 950 |
| Eritrea | 384 | 45 |
| South Sudan | 900 | 560 |
| Uganda | 1,180 | 285 |
| Libya | 56 | 96 |
| Chad | 322 | 413 |
| Saudi Arabia | 59 | 166 |
| United Arab Emirates | 78 | 6.5 |
Average annual rainfall in Sudan and its neighborhood, highlighting the small totals in Egypt and Gulf states.
(1) millimeter of rain = (1) liter of water spread over one square meter.
For the Sudanese, floods are the most harmful aspect of climate change. They are growing both more extreme and more frequent. Only an international consensus to cut greenhouse gas emissions and shift to alternative energy, fiercely opposed by oil and gas interests, can reduce the damage. Until then, local action is essential: secure advanced technology for early-warning systems; use them to enable anticipatory measures such as evacuations, clearing drains, scheduling planting, and safeguarding herds, saving money and reducing losses. Health authorities should prepare for water-borne and pollution-related diseases by ensuring vaccine supplies. And officials must prioritize funding and grant operational autonomy to the Environment and Agriculture ministries, the national meteorological service, civil defense, and relevant institutions so they can coordinate and act in concert to manage the priceless resource of rainfall, turning it from a life-threatening curse into a blessing that revives both land and people.
