Onion Prices Plunge 23% as Spring Bounty Highlights Climate-Driven Volatility

Wholesale onion prices in South Korea have fallen more than 20% from a year earlier, as favorable spring weather boosted yields and accelerated shipments of early-season onions, increasing supply pressure even as the planted area shrank.

According to the Korea Agro-Fisheries & Food Trade Corp. (aT) on Tuesday, the average wholesale price of premium-grade onions sold by intermediate distributors was 10,535 won per 15 kilograms between May 1 and 21, down 22.8% from the May average of 13,649 won a year earlier. The March average price was 13,229 won, down 52.2% year-on-year, and the April average price stood at 12,654 won, 45.7% lower.

Consumer prices have also weakened. As of May 21, the average consumer price of premium-grade onions stood at 1,838 won per kilogram, 22.3% below 2,364 won during the same period last year. Even accounting for the base effect from a higher loss rate of stored onions early last year, the rate of decline is steep.

This year, downward pressure on prices intensified as yields rose despite a smaller planted area. According to Statistics Korea, the planted area for the 2026 onion crop totaled 17,609 hectares, down 0.4% from a year earlier and 1.8% below the average year. By contrast, the Korea Rural Economic Institute (KREI) projected that the yield of mid- and late-season onions in May would reach 7,186 to 7,456 kilograms per 10 ares, up 1.2% to 5.0% from the previous year. That is also 4.9% to 8.8% above the average year.

Weather contributed to the higher yields. The nationwide average temperature in March was 1.3 degrees Celsius above the average year, and the April average was 1.7 degrees higher, the third-highest on record. April brought frequent rainfall in early in the month, followed by abnormally high temperatures in mid-April and dry conditions late in the month, but the combination of temperature and rainfall conditions allowed onions to grow smoothly, analysts said.

“This year’s rainfall and temperature aligned well with onion growth,” a Ministry of Agriculture, Food and Rural Affairs official said. “There were also few pest and disease problems, so the onions grew well and yields rose significantly.”

Onion prices are sensitive to supply-demand changes because the seasoning vegetable’s consumption cannot easily expand in the short term. Furthermore, early-season onions harvested from March through early May contain high moisture, making them difficult to store and often prompting immediate market release. When early-season onion shipments concentrate at once, surplus volumes are difficult to redirect to storage, inevitably increasing downward pressure on prices.

In recent years, onion prices have swung sharply with the weather. In 2022, a spring drought cut output by 24.2%, fueling upward pressure on prices. In 2025, by contrast, favorable weather conditions boosted yields and concentrated shipments, sending the average wholesale price of premium-grade onions to 790 won per kilogram in May and June, 29.9% lower than the same period a year earlier.

Limits of After-the-Fact Response… “Upgrade AI and Satellite-Based Supply-Demand Forecasting”

Farmers protesting the price decline have taken collective action. On May 15, the National Onion Producers Association held onion field plow-up protests at four locations nationwide, including Muan in South Jeolla Province, Wanju in North Jeolla Province, Gimcheon in North Gyeongsang Province and Hamyang in South Gyeongsang Province. Farmers said farmgate prices fell below production costs and demanded guaranteed minimum production costs and expanded public stockpile purchases.

The government has also taken action. It has already isolated 368 hectares of early-season onions with low storage durability from the market. Mid- and late-season onions, shipped from late May through the end of June, can be stored, allowing the government and the National Agricultural Cooperative Federation (Nonghyup) to adjust shipment timing through stockpiling. The Ministry of Agriculture is also reviewing an expansion of government stockpile purchases for mid- and late-season varieties.

The ministry also plans to support sorting costs for premium-grade onions secured by Nonghyup and distribution corporations with export experience, aiming to ship at least 2,000 tons abroad initially. Exports will be focused on regions with existing trade ties, such as Taiwan.

Cabbage prices have shown similar weather-driven swings. Last summer, heatwaves and torrential rain hurt quality and pushed retail prices above 7,000 won per head, but in early May this year, favorable spring growing conditions lowered prices to 3,523 won per head. That is 26% below a year earlier and 24% below the average year.

The challenge is that the impact of weather variables is set to grow further. Global warming is making extreme weather events such as high temperatures, torrential rain and drought more frequent, expanding uncertainty in agricultural supply and demand. Some analysts argue that supply-demand management must shift from an experience- and reaction-based approach to a data-driven, preemptive system. That means looking not only at output but also at consumption, storage and export capacity together.

“We need to integrate data from production through consumption using artificial intelligence (AI) and big data, and build a comprehensive supply-demand system,” said Kim Han-ho, professor of agricultural economics at Seoul National University. “To respond to price shocks, we also need to expand stockpiling capacity.”

The Ministry of Agriculture is also pushing to upgrade its supply-demand forecasting system. The ministry has previously announced plans to upgrade AI-based supply-demand forecasting models for major items including rice, horticultural products and livestock. Through the agriculture and forestry satellite scheduled for launch in the second half of this year, the ministry plans to collect information on planted and shipment areas of major crops to improve forecasting accuracy.