Ogallo is director of the IGAD Climate Prediction and Applications Centre in Nairobi, Kenya (formerly known as Regional Drought Monitoring Centre). He was previously lecturer, professor and chairman (1979-92) of the department of meteorology at the University of Nairobi. He has also served as secretary (CEO) of the Kenya National Council of Science and Technology (1992-94). His work on African climate has included studies of its variability and change change, modelling, prediction, early warning and climate risk proofing applications. He has been awarded the WMO Award for encouragement of young scientists in 1982. He was among the IPCC scientists who received the 2007 Nobel Price Award. He is an associate of the African Academy of Sciences and member of the Kenya Academy of Sciences.