This piece of code let you compute season length using definition of onset, cessation valid for sahelian region

season_length.R

# set up
pak::pak("YODAdam/ClimSeasonR")
library(tidyverse)
library(ClimSeasonR)

# read and clean daily data for multiple stations
data<-readxl::read_excel("~/Downloads/rain.xls",skip = 2) %>% 
  janitor::clean_names()

# compute season length, for a set of stations
data %>% 
  group_by(name) %>% 
  reframe(
    onset = dt_start(
      x = value,
      early = 91,
      maxDrySpell_aft = 10
    ),
    cessation = end_season(
      x=value
    )
  ) %>% 
  mutate(season_length = cessation-onset+1)