India recently entered a new phase of climate risk management with the launch of its first exchange-traded weather derivative. RAINMUMBAI’s debut on the NCDEX reflects the southwest monsoon’s unique importance in determining economic activity, writes Saumitra Bhaduri
l What is a weather derivative?
A WEATHER DERIVATIVE is a financial contract whose value (the contingent claim) is linked to an objectively measured weather variable (e.g., rain, temperature) rather than the price of a physical commodity such as wheat, crude oil or gold. The contract allows businesses and investors to transfer financial risks associated with abnormal weather to other market participants willing to assume them. Unlike conventional insurance, a weather derivative does not require proof that physical damage has occurred. Settlement depends entirely on the observed value of a predefined weather index. As the index moves above or below a specified benchmark, gains and losses are automatically determined in accordance with the contract specification.
l Specifications of RAINMUMBAI
RAINMUMBAI IS A standardised rainfall futures contract listed on NCDEX. The contract is based on Mumbai’s Cumulative Deviation Rainfall (CDR), which measures the cumulative difference between actual rainfall and the city’s long-term climatological average during the monsoon season. The benchmark, or Long Period Average (LPA), is computed by the India Meteorological Department (IMD) using observations from 1991 to 2020 and equals 2,206.7 millimetres. Separate futures contracts are listed for each of the four monsoon months from June through September.
l Why Mumbai was chosen
MUMBAI WAS SELECTED as the pilot location because it possesses one of the country’s longest and most reliable rainfall records, supported by two well-established IMD observatories with exceptionally high data availability. The city also represents India’s financial and commercial centre, where numerous industries are highly sensitive to rainfall variability. In addition, Mumbai experiences considerable rainfall volatility during the monsoon, providing sufficient variation to support active price discovery and hedging activity. These features make it a natural starting point before extending weather derivatives to other regions and weather variables.
l How is the spot price calculated?
THE SPOT VALUE is not determined by market transactions but is derived from a transparent index methodology. The RAINMUMBAI contract begins each season with the seasonal LPA as its initial reference value. Each day, the IMD records actual rainfall at the Santacruz and Colaba observatories. This observed rainfall is compared with the historical normal rainfall for the same calendar day. The difference between actual rainfall and the daily climatological normal constitutes the daily deviation. The cumulative spot value is then updated by adding this deviation to the previous day’s spot value. If rainfall exceeds the historical average, the cumulative index rises and vice-versa. Thus, the spot value continuously reflects cumulative departures from normal rainfall rather than the absolute amount of rain received.
l Why we need weather derivatives
AS CLIMATE RISKS get more frequent, businesses increasingly need instruments that protect not only physical assets but also revenues, operating margins and cash flows. Weather derivatives create a transparent market for transferring climate-related financial risk, reducing dependence on government relief and complementing traditional insurance mechanisms. If sufficient market liquidity develops, India could see derivatives on temperature, wind speed, and humidity, thereby creating a comprehensive market for climate risk management.
l Potential issues
THE FIRST IS market liquidity. Without sufficient participation from hedgers, institutional investors, and market makers, liquidity will remain limited, reducing the contract’s effectiveness as a hedging instrument. A second issue is basis risk from cross-hedging, whereby rainfall measured at designated IMD stations may not fully reflect the weather conditions experienced by businesses located elsewhere in the country. Third, successful weather derivative markets require high-quality, reliable and geographically dense weather data. Extending similar contracts to other regions would require comparable data quality. Fourth, many firms rely solely on insurance or informal coping mechanisms and may be unfamiliar with the role of derivatives in managing operational risks rather than speculative trading.
l Global weather derivative market
THE MODERN MARKET for weather derivatives originated in the US during the late 1990s when energy companies sought protection against unusually warm winters and cool summers that affected electricity and natural gas demand. Today, weather derivatives are traded through both organised exchanges and over-the-counter markets across North America, Europe and parts of Asia. Industry estimates place its annual size at $25 billion, although estimates differ depending on whether they measure exchange turnover, notional exposure or over-the-counter contracts.
The writer is professor, Madras School of Economics
Disclaimer: The views expressed are the author’s own and do not reflect the official policy or position of Financial Express.
