Many tropical regions sit close to dangerous heat thresholds, yet awareness of heat stress remains low across sub-Saharan Africa due to limited data and impact reporting. A recent study in Royal Meteorological Society's Weather journal represents an important step towards more understanding of how extreme heat translates into human impacts. This is a critical need in a warming climate.
An unusually intense heat episode affected Kenya in February 2024, raising public concern and prompting widespread media coverage. The challenge of how to respond to such extreme events came into focus during the spring 2025 visit of Jemimah Gacheru, Principal Meteorologist at the Kenya Meteorological Department (KMD), to UKCEH Wallingford through the National Capability for Global Challenges programme Visiting Scientist Scheme.
Jemimah worked with UKCEH Research Associate Guillaume Chagnaud on monitoring episodes of extreme heat, with the 2024 event serving as the catalyst for a collaboration between KMD and UKCEH researchers.
The resulting study, now published in Weather, used recently available high-resolution in situ observations alongside reanalysis data from the European Centre for Medium-Range Weather Forecasts to place the Kenya event in a broader climatological context and explore its underlying drivers.
The analysis showed that daily maximum temperatures and Heat Index values were on average 3–4°C above normal during the event, while wet-bulb temperatures remained near normal. This indicates that the episode was dominated by dry heat rather than humidity-driven stress. The heat was linked to a warmer-than-usual tropical atmosphere following the strong 2023 El Niño, clear sky conditions driven by an anticyclonic circulation that suppressed cloud cover, and unusually dry soils that intensified near-surface heating.
The work marks an important step toward improving understanding of heat impacts in East Africa. Following the study, KMD has begun issuing Heat Index forecasts for Nairobi, with plans – supported by ongoing collaboration with UKCEH – to expand these forecasts nationwide and across the wider region of East Africa through KMD’s role as a Regional Specialised Meteorological Centre.