Diurnal and seasonal dynamics of the canopy-layer urban heat island of Kuwait

This study examines the temporal and spatial variability of near-surface air temperature and the canopy layer urban heat island (UHI_CL) of Kuwait City. Observations collected at 12 locations across the country of Kuwait and for the period 2010–2022 are analysed on an hourly and 3-hourly basis to provide monthly and diurnal insights of the city's UHI_CL characteristics. Research on Kuwait's UHI_CL was first conducted by Nasrallah et al. (International Journal of Climatology, 10, 401–405). Results presented here have been afforded the benefit of additional stations and more extensive data compared with the earlier study. Mean positive UHI_CL intensities, ranging from 1.1°C to 3.8°C at night, are observed consistently across all months, owing to the prevalence of clear skies from winter to summer. Negative UHI_CL intensities, indicating a typical daytime urban cool island (UCI_CL), are most prominent on summer days, exhibiting a mean hourly magnitude range between 0.6°C and 2.6°C that extends into the early parts of the evening. Heat and cool island effects are maintained up to wind speeds approaching 10 m s⁻¹ at the urban periphery. A coastal site near the city demonstrates strong influences of the Arabian Gulf temperatures and associated sea and land breeze effects on UHI_CL development. The results can be used for comparison with other desert locales, in the evaluation of urban climate models, for urban planning policies and improving local weather forecasts. This study honours in memoriam Dr. Hassan Nasrallah, who produced the first UHI_CL study in the Arab World.