Weather Index Insurance & What Does Deficit Rainfall Pay?

Weather index (parametric) insurance pays out based on a measured weather variable — typically rainfall recorded at a reference station — rather than on a survey of your actual field loss. If the measured value crosses a defined trigger, the policy pays automatically. It's fast and transparent because no claim visit or loss assessment is needed; the gauge decides the payout.

Between the trigger and the exit level, the payout rises linearly with the shortfall. Payout fraction = (trigger − measured rainfall) ÷ (trigger − exit), capped at 0 above the trigger and at 1 (full payout) at or below the exit. The payout amount is that fraction × the sum insured. This tool computes the fraction, the amount and the shortfall for you.

The trigger is the rainfall level at which payouts begin — above it, there's no payout because rainfall is considered adequate. The exit is the level at which the full sum insured is paid — at or below it, the crop is assumed a total weather loss. Between trigger and exit, the payout scales linearly with how far rainfall fell short.

A survey-based claim needs an inspector, takes time and can be disputed. A rainfall index uses an objective, automatically recorded number, so payouts are fast, predictable and free of claim disputes or surveyor visits. The trade-off is basis risk — your field might suffer more or less than the gauge implies — but for many farmers the speed and certainty are worth it.

Basis risk is the gap between the measured index and your actual loss. The rainfall station might record adequate rain while your specific plot stayed dry, or vice versa, so you could get less (or more) than your true loss. Choosing a nearby, representative reference station and a well-set trigger reduces basis risk, but it can't be eliminated entirely.

The payout fraction is the share of the sum insured you receive — 0 when rainfall is at or above the trigger, 1 (100%) at or below the exit, and a proportionate value in between. Multiplying the fraction by the sum insured gives the payout amount. The tool shows the fraction so you can see exactly how the trigger and exit shape your cover.

Yes — the trigger/exit, linear-payout structure is the basis of weather-based crop insurance schemes (such as WBCIS) used for rainfall, temperature or humidity indices. This tool models the rainfall-deficit case; enter your scheme's trigger, exit, measured rainfall and sum insured to estimate the payout under its term sheet.

This tool models the deficit (drought) case, where payouts rise as rainfall falls below the trigger. Excess-rainfall or other indices follow the same linear trigger/exit logic but in the opposite direction. The deficit model covers the most common rainfall-shortfall product; for excess cover, mirror the trigger and exit accordingly.

Yes. Parametric weather insurance is used worldwide for crops, and the trigger/exit/linear-payout maths is universal. Choose your currency and enter your policy's rainfall trigger, exit, measured rainfall and sum insured to estimate the payout anywhere.

No — it's a planning estimate. Real payouts follow your policy's exact term sheet, reference station data and definitions. Use this tool to understand how a parametric product works and to estimate likely payouts, then confirm against your insurer's term sheet.