ck_pet: Potential Evapotranspiration (Hargreaves Method)
In climatekit: Unified Climate Indices for Temperature, Precipitation, and Drought

ck_pet

R Documentation

Potential Evapotranspiration (Hargreaves Method)

Description

Estimate daily PET using the Hargreaves-Samani equation, which requires only daily temperature extremes and latitude.

Usage

ck_pet(tmin, tmax, lat, dates)

Arguments

`tmin`	Numeric vector of daily minimum temperatures (degrees C).
`tmax`	Numeric vector of daily maximum temperatures (degrees C).
`lat`	Numeric. Latitude in decimal degrees.
`dates`	Date vector of the same length as `tmin`.

Value

A data frame with columns date, value, index, and unit.

References

Hargreaves, G. H., & Samani, Z. A. (1985). Reference crop evapotranspiration from temperature. Applied Engineering in Agriculture, 1(2), 96-99.

Examples

dates <- as.Date("2024-07-01") + 0:9
tmin <- c(15, 16, 14, 17, 15, 13, 16, 14, 15, 16)
tmax <- c(30, 32, 28, 33, 31, 27, 34, 29, 30, 32)
ck_pet(tmin, tmax, lat = 45, dates = dates)

climatekit documentation built on May 9, 2026, 5:08 p.m.