Onion, tomato, potato prices: Which months see the biggest jumps, and why?

Onion prices typically see their sharpest seasonal increases in February-March and August-September, while tomatoes are most vulnerable to price swings in July and potatoes in December, according to historical wholesale price patterns highlighted by Zerodha Markets. These seasonal movements offer clues to when household budgets may face pressure, particularly as food inflation rises and concerns over India’s monsoon and reservoir levels raise questions about agricultural supplies.

The data, based on usual month-to-month changes in wholesale prices between 2010 and 2022, shows that onion prices typically rise 31% in February and 30% in March. Another 30% increase is recorded in both August and September. For tomatoes, July stands out, with a typical monthly price move of 58%, followed by 47% in December and 43% in both February and June. Potato prices show their biggest typical monthly movement in December, at 26%, followed by 22% in March.

The patterns reflect the different production, harvesting and storage cycles of the three vegetables. However, the figures represent historical monthly price movements rather than forecasts of future increases.

Why onion prices jump before harvests

Onion prices are particularly sensitive to the timing of harvests, the availability of stored stocks and the arrival of fresh produce in wholesale markets. When supplies tighten between harvest cycles, prices can rise sharply. Storage conditions and crop losses can further influence availability, while changes in demand can amplify price movements.

MUST READ: India's retail inflation rises to 5.54% in September; food inflation hits 7.74%

The February-March and August-September patterns suggest that the periods preceding major harvest arrivals can be important for onion prices. However, the actual direction and magnitude of prices in any given year will depend on production, weather conditions, stock levels and the pace at which fresh supplies reach mandis.

Why tomato prices are volatile in July

Tomatoes show a different seasonal pattern, with July recording the largest typical monthly price movement. Their high perishability makes prices particularly sensitive to disruptions in harvesting, transport and market arrivals. Heavy rainfall, heat stress, crop disease or damage to growing areas can reduce supplies quickly, triggering sharp price changes.

Unlike onions and potatoes, tomatoes have limited scope for conventional long-term storage. Consequently, even temporary supply disruptions can have a disproportionate impact on wholesale prices. December also records a substantial typical price movement of 47%, underlining that volatility is not confined to the monsoon months.

ALSO READ: Chicken thali up 5%, veg meal 1% costlier in August: Onion jumps 43%, oil and LPG rise; potato-tomato ease

Why potatoes see their biggest move in December

Potatoes show relatively calmer price movements through much of the year, according to the chart, but December stands out with a typical monthly movement of 26%. March also records a relatively large movement of 22%.

Cold-storage stocks, harvesting cycles, demand and the pace of fresh arrivals influence potato prices. Storage allows potatoes to be held for longer than tomatoes, helping moderate some short-term supply shocks. Nevertheless, changes in stock availability and seasonal demand can still cause significant price fluctuations.

Food inflation adds to household pressure

India’s retail inflation rose to 5.54% in September 2026, while food inflation climbed to 7.74%. Wholesale inflation surged to 11.39%, amid broader price pressures that included rising energy costs linked to the US-Israel war on Iran.

The inflation outlook is also complicated by concerns over deficient monsoon rainfall and declining reservoir levels. According to figures cited in a report examining the agricultural implications, 48% of India’s 734 districts received deficient rainfall, while reservoir storage stood at 126.7 billion cubic metres as of October 15, 24% below the year-earlier level.

DON'T MISS: Govt starts buffer onion releases as festive demand nears

The potential implications extend beyond vegetables. Water availability, rabi sowing and crop yields could influence supplies of cereals and pulses in the coming months, although the eventual impact will depend on irrigation, winter rainfall, existing stocks and government intervention.

For households, the seasonal price calendar offers a useful guide to periods when vegetable prices have historically been more volatile. For policymakers, the challenge is to distinguish temporary supply disruptions from sustained inflationary pressures. Historical patterns can help identify vulnerabilities, but actual prices will depend on the interaction of weather, harvests, storage, transport and market demand.