Measuring Urban Heat Island Intensity in London During the Warmest June on Record

Understanding and managing urban heat is important for climate mitigation planning, requiring spatially and temporally detailed air temperature data. This study applies a distributed network of 25 bespoke LoRaWAN air temperature sensors to examine Urban Heat Island Intensity (UHII) across London during June 2025, the warmest June on record. Results show a maximum UHII of 2.8°C, with significant intensification during two major heatwaves, and stronger nocturnal intensity. The findings also demonstrated the efficacy of low-cost, distributed sensing for monitoring extreme urban heat and informing local climate resilience strategies.