Empirical Assessment of Urban Microclimate Modification in Ibadan: Implications for Urban Heat and Outdoor Comfort

Urban microclimate modification in rapidly growing tropical cities creates thermal environments that significantly affect outdoor human comfort, energy demand, and public health. This study empirically assesses urban microclimate modification in Ibadan, Oyo State, characterizing urban-rural thermal contrasts and outdoor thermal comfort conditions across urban land use gradients. Mobile transect measurements of air temperature, relative humidity, wind speed, and solar radiation were conducted during dry and wet seasons of 2022 and 2023, along four traverses from the urban core to rural periphery. Fixed reference measurements from IITA Ibadan and NiMet Ibadan Airport stations provided temporal anchoring. The Universal Thermal Climate Index (UTCI) was computed from measured parameters at all transect points and analyzed against land use and land cover classes from a 2023 Sentinel-2 classification. Results document mean urban-rural temperature differentials of 2.1 degrees Celsius during daytime and 3.4 degrees Celsius at night, with high-density commercial and residential zones generating the strongest UHI signal. UTCI analysis reveals that 78 percent of urban core transect points fall in the strong or very strong heat stress category during dry-season afternoon periods, compared to 32 percent of rural reference locations. Green space and tree canopy coverage emerge as the strongest spatial predictors of UTCI reduction, with each 10 percent increase in canopy cover associated with a 1.2 degrees Celsius reduction in mean radiant temperature. Keywords: urban microclimate, UTCI, Ibadan, heat stress, outdoor comfort.