Precipitation, temperature and potential evapotranspiration for 1991–2020 climate normals over Africa

Precipitation and temperature variability and change across Africa significantly impact the continent’s key socio-economic sectors such as agriculture, water resources, health and infrastructure development. Despite experiencing the highest warming in the past decades, Africa’s most recent climate normals are yet to be documented. This study presents the latest climate normals, 1991–2020, as defined by the World Meteorological Organization (WMO) for key variables: precipitation, temperature (mean, minimum and maximum), and potential evaporation (PET). Analysing monthly observational data from the Climatic Research Unit (CRU) version 4.07, we examine the spatio-temporal variability of these variables over Africa and its nine climate sub-regions during 1991–2020, and changes relative to the baseline climate normals (1961–1990) and previous normal periods (1971–2000 and 1981–2010). We employ anomaly and trend analysis to investigate changes during the different periods, while empirical orthogonal function (EOF) is used to identify dominant seasonal patterns. Distinct precipitation characteristics emerge across the sub-regions, with the Mediterranean (MED) and Madagascar (MDG) exhibiting a consistent decreasing trend since 1961–1990, while other regions experience an increase compared to the last normal period (1981–2010). The Sahara (SAH), Western Africa (WAF), and Northern Eastern Africa (NEAF) show higher precipitation during 1991–2020 than in 1961–1990. Mean temperature shows an overall increase across Africa, with MED, SAH and Eastern Southern Africa (ESAF) recording the highest temperature rise of 0.79, 1.71 and 0.68 °C, respectively, compared to 1961–1990. Similar trends are reflected in minimum and maximum temperatures. PET patterns align closely with temperature changes, particularly in SAH, where PET increases by 35.7 mm during the last climate normals compared to 1961–1990. The EOF results agree with the climatological means. However, a decrease in the percentage variance of the dominant modes across the periods for temperature and PET suggests possible shifts in climate oscillations or dynamics. This study contributes vital insights into observed and expected climate trends over Africa, benefiting the scientific community, stakeholders, and end-users. The results emphasise the urgency of climate adaptation measures in Africa and underscore the necessity for proactive strategies to address climate change impacts.