> For the complete documentation index, see [llms.txt](https://swatplus.gitbook.io/io-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swatplus.gitbook.io/io-docs/introduction-1/climate/weather-wgn.cli/pcp_skew.md).

# pcp\_skew

This parameter quantifies the symmetry of the precipitation distribution around the monthly mean. The skew coefficient is calculated as

$$
g\_{mon}=\frac{N\*∑*{d=1}^N\*(R*{day,mon}-R\_{mon})^3 }{(N-1)*(N-2)*(σ\_{mon})^3}
$$

where $$g\_{mon}$$ is the skew coefficient for precipitation in the month, $$N$$ is the total number of daily precipitation records for month $$mon$$, $$R\_{day,mon}$$ is the amount of precipitation for day $$d$$ in month $$mon$$ (mm H2O), $$R\_{mon}$$ is the average precipitation for the month (mm H2O), and $$σ\_{mon}$$ is the standard deviation for daily precipitation in month $$mon$$ (mm H2O). Daily precipitation values of 0 mm are included in the skew coefficient calculation.