Heat-constrained potential accessibility to outdoor sport facilities in France: A dynamic supply framework for spatial planning

Spatial accessibility indicators assume that facilities within reach are available whenever residents wish to use them. For outdoor sport facilities, heat breaks this assumption. We develop heat-constrained potential accessibility, in which the supply of each facility is scaled by its hourly thermal availability. Availability is derived from regional wet-bulb globe temperature (WBGT; ERA5-Land, 1991–2020) modified by facility attributes: cover, tree canopy and surface type. We apply the model to 97,816 public outdoor facilities and 62.6 million residents of metropolitan France, at 200-m resolution, with a 15-min walking catchment and a 26 °C WBGT threshold. On July afternoons, heat removes on average 25% of potential accessibility, and at least 47% in Occitanie, Provence-Alpes-Côte d'Azur and Corsica. Served residents spend 139 h per season without any heat-available facility within reach, and 156 h in 2006–2025. Magnitudes depend strongly on the threshold (11% peak loss at 28 °C), whereas spatial rankings are stable. A regional WBGT without facility attributes underestimates mean losses by 12–15%. After regional standardisation, peak losses differ little across income groups, but desert exposure increases with income, in association mainly with the number of facilities within reach and secondarily with their peak availability. Under idealised complete shading, shading 5% of facilities chosen to maximise coverage removes 68% of heat-attributable desert person-hours (50% with half shade), against 21% when the hottest facilities are shaded first. Heat-constrained accessibility turns climate exposure into a property of supply that planners can map, compare and target.