How El Nino Affects Turkey: Rainfall, Agriculture and Hydropower

Published: July 26, 2026 · 10 min read

Climate Crossroads: Why Turkey's El Nino Response Is Uneven

Turkey's geography makes it one of the more complex countries to characterize in terms of ENSO teleconnections. The country spans approximately 1,600 km east to west and 600 km north to south, covering three distinct climate regimes. The Mediterranean and Aegean coasts have a subtropical Mediterranean climate with mild, wet winters and hot, dry summers. Central and eastern Anatolia have a continental climate with cold, snowy winters and hot summers, and precipitation peaking in spring. The Black Sea coast has a temperate oceanic climate with year-round rainfall, receiving 2,000-2,500 mm annually in the eastern Black Sea region — among the highest precipitation totals in the Northern Hemisphere mid-latitudes.

El Nino's teleconnection to Turkey runs primarily through the Mediterranean storm track. During El Nino winters, the subtropical jet stream strengthens and shifts southward across the Mediterranean basin. This shift tends to pull winter cyclones — the Mediterranean lows that deliver the bulk of Turkey's cold-season precipitation — toward North Africa and the central Mediterranean, reducing the number of storms that track across Turkey. Research by Turkes and Erlat (2005), analyzing Turkish precipitation data from 1930-2000, found a statistically significant negative correlation between Nino 3.4 sea surface temperatures and winter precipitation across western and southern Turkey.

A 2018 study in the International Journal of Climatology refined this picture, showing that the precipitation reduction is strongest in the Marmara, Aegean, and Mediterranean regions (10-30% below normal during moderate-to-strong El Nino winters), weaker in Central Anatolia (5-15%), and absent or reversed in the eastern Black Sea region, where some stations show a slight precipitation increase during El Nino.

Rainfall Patterns: The Mediterranean-Western Deficit

The 2015-16 El Nino provides the most recent strong-event case study for Turkey's precipitation response. According to the Turkish State Meteorological Service (TSMS), the 2015-16 water year (October-September) produced significant regional disparities.

Istanbul recorded 623 mm of precipitation for the 2015-16 water year, against a long-term average of 824 mm — a 24.4% deficit. The shortfall was concentrated in the winter months: December 2015 through February 2016 saw only 191 mm, compared to a winter average of 269 mm. Izmir, on the Aegean coast, recorded 507 mm against an average of 689 mm, a 26.4% deficit. Antalya, on the Mediterranean coast, recorded 809 mm against 1,058 mm, a 23.5% deficit.

The spatial pattern was consistent with the El Nino teleconnection: precipitation deficits were largest in the west and south, modest in the interior, and absent in the northeast. Trabzon, on the Black Sea coast, recorded 872 mm against an average of 826 mm — a 5.6% surplus, consistent with the Black Sea exception pattern.

This precipitation reduction matters because Turkey's winter rainfall is critical for reservoir recharge, groundwater replenishment, and soil moisture accumulation for the spring growing season. Unlike many tropical and subtropical countries where El Nino's effects manifest in a single season, Turkey's impacts cascade through the entire water year: a dry winter means low reservoir levels in spring, reduced irrigation availability in summer, and stressed dryland crops at harvest.

Central Anatolia: Wheat, Barley, and the Konya Basin

Central Anatolia is Turkey's agricultural heartland, producing roughly 35% of the country's wheat and 40% of its barley. The region has a semi-arid continental climate with annual precipitation of 300-400 mm, most of it falling in winter and spring. Farming is a mix of rain-fed production on the Anatolian plateau and irrigated production in basins served by groundwater and reservoirs.

The 2015-16 El Nino reduced Central Anatolian wheat production significantly. The Turkish Statistical Institute reported that national wheat production fell from 22.6 million tons in 2015 to 20.1 million tons in 2016, an 11% decline. The reduction was concentrated in rain-fed areas of Central Anatolia, where winter-spring precipitation was 15-25% below normal. In Konya province — Turkey's single largest wheat-producing region — the harvest dropped by approximately 18%, according to provincial agricultural directorate data.

The Konya Basin, a closed basin in southern Central Anatolia that produces wheat, sugar beets, and sunflowers, faces a deeper challenge. Groundwater levels in the basin have dropped by an estimated 1-3 meters per year over the past two decades, according to a 2020 study in Hydrogeology Journal, driven by the expansion of irrigated agriculture from roughly 100,000 hectares in 2000 to over 500,000 hectares by 2020. The estimated number of illegal wells in the basin exceeds 100,000, far outstripping the recharge rate. El Nino drought years accelerate drawdown: when winter precipitation is low, farmers pump more groundwater to compensate, and the following year's starting water table is lower than it would have been otherwise.

Turkey's agricultural export position is sensitive to these production swings. Turkey exported approximately 3.5 million tons of wheat in 2015 but increased imports to 4.2 million tons in 2016, a net trade swing of roughly 3.5 million tons worth approximately $700 million at prevailing prices. The shift was driven partly by the El Nino-related production shortfall and partly by policy decisions (Turkey had also opened imports to stabilize domestic flour prices).

The Black Sea Exception: Tea, Hazelnuts, and Shifted Storm Tracks

The Black Sea region is a notable exception to El Nino's drying influence on Turkey. When the Mediterranean storm track shifts southward during El Nino, some cyclones are deflected northeastward around the high-pressure ridge that forms over eastern Europe, steering them into the Black Sea basin. The result can be near-normal or above-normal precipitation along Turkey's Black Sea coast.

The 2015-16 winter reflected this pattern. While Istanbul was 25% below normal, Rize — on the eastern Black Sea coast — recorded 1,243 mm of precipitation for the water year, against an average of 2,233 mm. This was actually slightly below normal, illustrating that the Black Sea "exception" does not always mean a precipitation surplus — it means the region does not share the deficit pattern that dominates the rest of western and southern Turkey.

The agricultural significance of the Black Sea region lies in its specialty crops. Turkey produces approximately 70% of the world's hazelnuts, and the bulk of this production is concentrated along the Black Sea coast, particularly in the provinces of Ordu, Giresun, and Trabzon. Hazelnut trees require consistent moisture, and the Black Sea climate delivers it reliably — the region receives precipitation in all months. Turkish hazelnut production is thus largely insulated from El Nino, which is one reason why global hazelnut supply does not show strong ENSO-linked volatility.

Tea production, concentrated in Rize province, is similarly stable. Turkey is the world's fifth-largest tea producer, and its Black Sea tea gardens depend on year-round precipitation. Unlike the drought-sensitive crops of Central and Western Anatolia, Black Sea tea and hazelnut production are buffered by the region's perennially wet climate.

Hydropower: Dams, Snowpack, and Electricity Output

Turkey generates approximately 25-30% of its electricity from hydropower, with installed hydro capacity of roughly 32,000 MW as of 2026. The country's largest dams are concentrated in two regions: the Euphrates-Tigris headwaters in southeastern Anatolia (the Ataturk Dam, Karakaya Dam, Keban Dam, and the massive Ilisu Dam) and river systems in northern and western Anatolia.

El Nino affects Turkish hydropower through two channels: winter precipitation directly feeding reservoir inflows, and winter snowpack in the eastern Anatolian highlands, where meltwater sustains river flow through the spring and early summer. A snowpack deficit during an El Nino winter means reduced melt-season flow in April-June, precisely when irrigation demand and electricity demand both rise.

The 2015-16 El Nino demonstrated this mechanism. Reservoir levels at the Ataturk Dam — Turkey's largest, with 2,400 MW capacity — dropped to 28% of capacity by November 2016, one of the lowest levels since the dam opened in 1992. The combination of below-normal winter precipitation and a reduced snowpack in the eastern Taurus Mountains reduced Euphrates flow. Turkey's total hydropower generation fell from 67.1 TWh in 2015 to 67.3 TWh in 2016 — a modest decline, but the monthly pattern was more revealing: generation in the first half of 2016 was notably below normal, with natural gas-fired plants picking up the shortfall.

The Southeastern Anatolia Project (GAP), Turkey's massive integrated development scheme for the Euphrates-Tigris basin, involves 22 dams and 19 hydropower plants. During El Nino years, the trade-off between hydropower generation and downstream water commitments becomes acute. Turkey's agreements with downstream riparian states — particularly the 1987 protocol guaranteeing Syria a minimum flow of 500 cubic meters per second on the Euphrates — come under pressure when reservoir levels are low. For the 2026-2027 El Nino, the GAP reservoirs' status will be closely watched by water managers in both Turkey and downstream Iraq and Syria.

2026-2027 Outlook for Turkish Agriculture and Water Resources

For the 2026-2027 very strong El Nino, seasonal forecast models project a familiar pattern for Turkey. The ECMWF seasonal outlook as of July 2026 assigns a 60-70% probability of below-normal precipitation for the December-February period across western and southern Turkey, and a 45-55% probability for Central Anatolia. The Black Sea region shows no significant signal either way.

Winter wheat planting in Central Anatolia, which takes place in October-November 2026, will depend on autumn soil moisture rather than winter precipitation directly. As of July 2026, soil moisture conditions across Central Anatolia are near the long-term average, suggesting that the autumn planting window should be viable. The critical period will be March-May 2027, when winter wheat requires moisture for grain filling. If the 2026-27 winter follows the typical El Nino pattern of reduced precipitation, spring soil moisture will be a constraint.

For hydropower, the outlook depends on reservoir levels entering the winter. As of late July 2026, Turkey's major reservoirs are at roughly 55-60% of capacity — slightly below the seasonal average of 65%. A dry winter could push levels below 40% by spring 2027, which would force increased reliance on natural gas generation and potentially pressure electricity prices. Turkey's natural gas import bill, already sensitive to global LNG prices, would increase in this scenario.

Water managers at Turkey's State Hydraulic Works (DSI) monitor ENSO forecasts as part of their seasonal planning. In previous strong El Nino years, DSI has implemented water-use restrictions in the Konya Basin and parts of the Aegean region to preserve reservoir levels. Similar measures are plausible for 2027 if winter precipitation does not recharge reservoirs adequately. The GAP region's reservoir management in 2027 will also require balancing domestic hydropower generation with international flow commitments — a perennial challenge that El Nino makes more acute.