El Niño in Vietnam: Central Highlands Drought and the Robusta Coffee Crop

Vietnam supplies the large majority of the world's robusta coffee, and that coffee grows in a region whose water security depends on a wet season that El Niño weakens. That single fact is why an ocean anomaly in the central Pacific ends up in the price of instant coffee.

With El Niño declared in June 2026 and a peak forecast for October-December, the exposed window — the Central Highlands dry season — falls in the first months of 2027.

The Central Highlands and the irrigation window

Robusta is concentrated in Đắk Lắk, Lâm Đồng, Gia Lai and Đắk Nông. The crop depends on stored water and groundwater through a dry season that runs roughly January to April, and that storage is set by the wet season before it.

El Niño reduces wet-season rainfall across mainland Southeast Asia. Reservoirs and water tables enter the dry months lower. Growers irrigate anyway — from wells that then draw down faster — and in severe years the wells run dry before the rains return. In 2015-16 and 2019-20 that sequence produced measurable losses and, more damagingly, stressed trees whose yields stayed depressed into subsequent seasons.

The lag is worth stating plainly, because coverage often gets it wrong: the drought hits the harvest that follows it, not the one being picked.

Why robusta is not interchangeable with arabica

A robusta shortfall is not neatly covered by Brazilian arabica. The two beans serve different products — robusta dominates instant coffee and carries the body in most espresso blends — and roasters cannot switch freely without changing what they sell.

That partial substitutability is why the robusta-arabica spread moves on Vietnamese weather rather than the two prices simply tracking together. When Brazil and Vietnam are stressed in the same event, as El Niño can arrange, the market has no comfortable side to lean on. Our coffee prices page follows both halves.

The Mekong Delta: salt instead of drought

Vietnam's second exposure is different in kind. The Mekong Delta produces the country's rice surplus, and in the dry season it faces salinity intrusion — seawater pushing inland up the channels as river flow falls.

How far the salt front travels depends on upstream flow, which depends on rainfall across the whole basin. El Niño reduces that rainfall. The 2015-16 event drove one of the most severe intrusions on record, damaging paddies and fruit orchards well inland, and the recovery took multiple seasons because salt does not leave the soil when the rain returns.

Rice is the visible loss. The slower one is perennial fruit, which cannot be replanted the following season.

What to watch

For Vietnam the useful indicators are the wet-season rainfall total in the Central Highlands, because it sets the buffer, and the reported position of the salt front in the delta through February and March.

Current ocean readings are on the live dashboard, and the Southeast Asia page covers the regional pattern this sits inside.