Matina, in Limón province, received 532.8mm of rain in the 21 days to 28 August, the highest for the period since the data series began in 1940, according to ERA5 reanalysis. The previous high was 515.4mm in 2002.

The deluge hit a swathe of the export belt responsible for the majority of production in Costa Rica's banana industry. All five of Cropli's Caribbean monitoring points ranked among their eight wettest.

President Laura Fernández declared a national emergency in nine cantons on 20 August under executive decree 45910-MP, as reported in the official gazette La Gaceta.

Parts of Matina, Guácimo and Siquirres received up to 280mm on 15 and 16 August, more than a plantation normally needs in a month. Some fields stayed under water for as long as 36 hours, the Tico Times and FreshPlaza reported on 30 and 31 August.

Erick Bolaños, director of technical assistance at the Corporación Bananera Nacional, known as Corbana, said producers were already seeing damage but that it remained too early to predict a large fall in exports.

Waterlogging damages root systems even on farms with drainage. The consequences, weaker plants, less leaf area and fewer bananas meeting export specification, take 10 to 12 weeks to appear, Corbana said in June.

Warmth and standing water also favour black sigatoka, a leaf fungus that cuts the plant's photosynthetic area and can ripen fruit early, and moko, a bacterial wilt that travels between plantation sections in floodwater.

EL NIÑO'S "TWO FACES"

Corbana had warned of the risk as forecasts pointed to a strong El Nino year. "El Niño historically has two faces in Costa Rica: the Pacific dries out and the Caribbean becomes rainier," Bolaños said in a corporation press note on 9 June, reported by Portalfrutícola.

"According to the historical data we have, when there have been moderate or strong El Niño effects, production conditions decline," he said.

He cited the 1997-98, 2008-09, 2014-15 and 2023 episodes, in each of which productivity measured in boxes per hectare fell. The corporation said at the time it was drafting an emergency protocol for extreme rainfall, to be made official within weeks.

Corbana is now coordinating the emergency plan with the Ministry of Agriculture and Livestock, the Tico Times and FreshPlaza reported in late August, almost three months after the corporation said it was weeks away. Growers are clearing drainage channels, repairing and building dikes, applying extra nutrients, stripping infected leaves and treating for sigatoka.

Landslides and closures on Route 32, the San José to Limón highway, have restricted access to farms and haulage to the Caribbean ports.

The next fortnight offers Matina no drainage window. ECMWF's 51-member ensemble puts median rainfall at Matina at 216mm for 4 to 18 September, against a 121mm normal for those days, and at Pococí at 237mm against 153mm. Even the driest of the 51 runs gives Matina 130mm, and the chance of exceeding 150mm there is 92 per cent.

The Instituto Meteorológico Nacional, the national weather service, expects Caribbean rainfall to run 10 to 15 per cent above normal for the rest of 2026, with temperatures 0.5C to 1C higher.

SECOND WET YEAR

This is the second consecutive year in which rain is the central problem for an industry that sold 125.5 million boxes of bananas in 2024: in September 2025 Corbana reported first-half exports down 20.7 per cent.

The group blamed rainfall that accumulated from late 2024 into early 2025 together with black sigatoka, and said its projections for 2026 already showed lower fruit availability than usual.

Prices have yet to react. Central American bananas at Rungis, the Paris wholesale market, averaged €1.11 a kilo, or about $1.29, in August against €1.05 in July, inside the €1.05 to €1.20 range the quotation has held since July 2025, on price data collected by Cropli.

Costa Rican exports were also running about 5 per cent ahead of last year through June, the trade reports said. Destination customs records, which count arrivals rather than export declarations, show a longer erosion in the English-speaking markets.

UK arrivals from Costa Rica in the first half fell to 79,762 tonnes from 125,523 tonnes in 2021, and Canada's to 37,577 tonnes from 78,195 tonnes, on HM Revenue and Customs and Statistics Canada figures accessed via Cropli.

Both are small beside the European Union, whose member states took about 479,000 tonnes in the first half of this year, roughly six times the UK total.