On the geometrical limitations of the globe thermometer for assessing pedestrian radiative exposure in outdoor settings

Rising urban temperatures, intensified by climate change, are increasing heat stress and driving greater cooling demands, particularly during heat waves. In this context, enhancing the resilience of urban environments is essential, and accurate evaluation of microclimatic conditions plays a crucial role in informing adaptive design strategies. The radiative environment significantly influences both outdoor and indoor spaces. Particularly, to assess human exposure to radiant heat, the mean radiant temperature ( Tmrt ) is often measured using cost-effective globe thermometers. Despite their widespread use, globe thermometers misrepresent Tmrt by overestimating shortwave radiation absorption, high thermal inertia, and averaging radiation from all directions, failing to capture the directional exposure of standing person. Specifically, the effect of measurement geometry on Tmrt has not been comprehensively examined in real-world urban settings. Based on a field campaign, this paper presents a methodology to recreate the 3D radiant environment of urban spaces, analysing how two body shapes—a globe (globe thermometers) and a cylinder (standing person)—affect radiative exposure. It aims to: (i) compare the contributions of longwave, direct, and diffuse shortwave radiation; (ii) evaluate influences on Tmrt and thermal indices; and (iii) assess the impact of urban characteristics on radiant exposure. Results show that the globe underestimates longwave and overestimates diffuse shortwave radiation and, at 44° solar elevation, it matches the cylinder’s direct radiation. The globe overestimates Tmrt , affecting thermal indices, especially in sun-exposed areas with high Sky View Factor. These results raise awareness of measurement techniques in outdoor microclimatic analysis, recreating the radiant environment from field data.