Urban climate results from the modifications caused by the characteristics of cities, which modifies the regional climatic conditions of a city. When urban areas are warmer than the surrounding areas, the urban heat island (UHI) phenomenon occurs. Being a major phenomenon and a global topic of interest for all affected cities, there are already numerous studies that address this subject. However, most studies are only focused on the macro and mesoscales. This study looks at the micrometeorological scale in a neighborhood of Lisbon (Telheiras). Having as a main objective to evaluate how the radiation balance of urban materials influences air temperature in an urban canyon, thermal images of different urban materials were obtained using infrared thermography, a technique that allowed understanding how the temperatures registered in the facades and other urban surfaces can affect the air temperature of the urban canyon. The components of the radiation budget were obtained by using a pyranometer and a pyrgeometer. Moreover, a microclimatic network to monitor air temperature and relative humidity was installed in the study area. The results show that, when the streets are less exposed to the prevailing wind direction in Lisbon (north and northwest), air temperatures are slightly higher than those found in opposite conditions. Both the temperature and the radiative balance of the facades and other surfaces (asphalt, light Portuguese sidewalk, and tile floor) respond directly to incident solar radiation. As expected, it was found that south facades have the highest temperatures of the four exposures under study (>4 °C when compared to the opposite facade), and the highest radiative balance was always registered on asphalt when compared to the sidewalk (at 9:00 a.m. + 30 W∙m⁻², at 1:00 p.m. + 149 W∙m⁻², and at 7:00 p.m. + 66 W∙m⁻²).

Regarding the predisposition of individuals to change when confronted with future climate scenarios, it is necessary to understand the perception of the groups under analysis and how to engage with society to collectively act toward climate change mitigation. A question remains to be answered: how to ensure that people engage, participate, and gain awareness of the undergoing problem that urban climate change poses for the future of cities’ management? This research intends to contribute to solving this question by raising another question: “How willing are residents of the Alvalade neighborhood (Lisbon) to change their behavior and way of life when faced with climate change scenarios?” We present a methodology using microclimatic modeling with ENVI-met and questionnaires for the resident community. The present and future local climate scenarios (representing a present hot day versus the extreme IPCC RCP 8.5 scenario) were presented to a set of residents. These figures show the projected UTCI (Universal Thermal Climate Index) in a dramatic but accurate aggravated way. The inquiries allowed us to conclude that people are more aware of local climate change and health risks from extremely hot summer weather, but they continue to resist adopting behavior change for adaptation, although most of them declared this could be important to tackle climate change. The second conclusion is that people think that local authorities should be more active than themselves and will have greater responsibility for climate change adaptation and interventions. In times of climate crisis, the participation of the resident community can be an important help in decision making and finding measures to mitigate adverse climate effects in urban environments.

Heat stress mitigation actions must be carefully planned in order to achieve effective outcomes. By integrating urban planning guidelines with urban climate knowledge, substantial benefits can be achieved for the community. In Lisbon, the study area, urban planning guidelines are strict in relation to the tree species which should be used for planting. This study examined these species environmental contributions to the community, especially in regard to heat stress mitigation in two urban canyons previously found as UTCI hotspots. For this, microclimatic Envi-met simulations were run which allowed recalculation of the UTCI hotspot analysis and to assess individual species contribution to possible mitigation efforts. Results demonstrated the ability of these trees to lower air temperature and the Universal Thermal Climate Index (UTCI). By reducing UTCI temperatures between 3.19 °C and 6.27 °C on a hot summer’s day, these trees were also able to transform an identified UTCI hotspot into a coldspot. From the studied species, Pyrus calleryana was found to be the most effective species for mitigating thermal stress, although all three species performed well. Regarding community services, according to the iTree tool, Cercis siliquastrum had the greatest overall impact. These results give to the municipal urban planning which tree species should be prioritized in terms of climate action, as well as a methodological framework to assess at local scale which areas should be intervened.

The thermal impact of vehicle surfaces on urban climate is a critical yet understudied component, with the potential to influence local microclimates and the urban energy balance. This research quantified the thermal effects of vehicle surfaces in Lisbon, Portugal, through a combination of in situ measurements and parametric modeling. Using a compact mobile weather station equipped with precise sensors, we conducted both mobile and stationary measurements to capture detailed data on the radiative properties of vehicle surfaces. Results revealed significant variations in surface temperatures based on vehicle color. Black vehicles reached a median surface temperature of approximately 71°C, about 20°C higher than white vehicles, which had a median surface temperature of 45°C. This difference in heat absorption directly affected local air temperatures: black vehicles increased surrounding air temperatures by around 2.5°C on a summer day, while white vehicles caused a more moderate rise of 1°C. Black vehicles also exhibited the highest median net all-wave radiative balance (752.8 W/m²), while white vehicles showed much lower values (515 W/m²), illustrating darker vehicles’ greater thermal load and localized heating effects. When exposed to direct sunlight, dark grey vehicles showed the highest radiative balance values (median 680 W/m²), while white vehicles demonstrated the lowest values, confirming their reflective nature. To complement field measurements, we conducted thermal simulations using EnergyPlus integrated with Honeybee for Grasshopper. These simulations, calibrated with site-specific meteorological data, were used to assess whether the 3D EnergyPlus models could replicate real-world conditions. The results validated observed trends and deepened understanding of vehicle characteristics’ role in influencing surface and air temperatures. This study bridges the gap between empirical data and simulations, offering valuable insights for urban climate research and informing mitigation strategies to reduce urban heat island effects.