Observed Changes and Variability in wet days and Dry Spells over IGAD region of Eastern Africa

Abstract Extreme Rainfall is crucial for Crop production and food security in Eastern Africa. This paper seeks to investigate the changes and variability in wet days and dry spells over the IGAD region. Data used are Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS). Several statistical methods and wet days and dry spells thresholds at ≥ 1mm applied on decadal (10 years), 20, 30 and 41 years. The results show that decrease in the number of wet days lead to longer dry spells. The majority of districts in Uganda, southwestern South Sudan, southwestern zones in Ethiopia, highlands of western and Nyanza counties in Kenya observed the highest number of wet days (50–70 days) and lowest consecutive dry spells (0–1 spells). Uganda and South Sudan are the two countries with lowest variability on wet days (highest variability in dry spells). Again, South Sudan and Uganda, most parts of Ethiopia, highlands of western Kenya observed 90–100% probability of exceeding 7 and 14 days (1 and 2 spells) during March-May (MAM), June-August (JJA) and September-November (SON). Northeastern Kenya and Somalia, southeastern Ethiopia, most parts of Eritrea and Djibouti observed less than 5% of probability under 7, 14,21,28 days (1,2,3,4 spells). In addition, most parts of the region observed decreased number of wet days in the 1980s and 1990s, while the last decade (2011–2020) experienced an increase during MAM and JJA. These findings are important for rain-fed agriculture, supplementary irrigation planning and food security in the IGAD region.