Extreme heat is an important and increasingly persistent climate risk in Lagos. Evidence from the PALM TREEs project shows widespread heat stress across the study locations, with none recording heat stress below 35°C.

High temperature combined with high humidity substantially increases heat discomfort, particularly during the dry season. March recorded the highest average Humidex values and the greatest frequency of heat-stress days. Heat exposure is also spatially differentiated. Heat hotspots are particularly prominent in the southern portion and city centre, while Urban Heat Island effects were identified in the city centre. The vulnerability is not evenly distributed. Approximately 75.5% of respondents work outdoors, while 46.3% of households experience high thermal housing vulnerability and a further 47.2% experience moderate vulnerability. In addition, 91.3% of households depend on a single income source, constraining their capacity to absorb the economic effects of prolonged heat. The lived experience of heat is substantial. Approximately 95% of weather-diary participants reported feeling hot during February and early March, with persistent discomfort reported during the February–April observation period. The study also indicates increasing heatwave severity and duration, with heat conditions extending across two to four months during the dry season. These findings are particularly relevant to Lagos’s existing climate policy architecture. The State’s Climate Action Plan 2020–2025, Lagos Resilience Strategy, and more recent Lagos Climate Adaptation and Resilience Plan (LCARP) already establish a policy basis for climate resilience. LCARP specifically identifies extreme heat as a major climate