Drought Index Calculator

Approximate drought severity using simplified Palmer and SPI methods from monthly climate data.

Monthly Precip (inches)

Normal Monthly Precip (in)

Mean Temperature (°F)

Precip Std Dev (in)

Available Soil Moisture (inches)

Simplified PDSI

SPI Value

Precip Deficit

Soil Moisture

4.0+: Extremely wet

2.0 to 3.99: Very wet

-1.99 to 1.99: Near normal

-2.0 to -2.99: Moderate drought

-3.0 to -3.99: Severe drought

-4.0 or below: Extreme drought

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