The increasing frequency and intensity of heat waves, combined with urban heat islands (UHIs), pose significant public health challenges. Implementing low-cost, real-time monitoring networks with distributed stations within the smart city framework faces obstacles in transforming urban spaces. Accurate data are essential for assessing these effects. This paper compares different network types in a medium-sized city in western Spain and their implications for UHI identification quality. The study first presents a purpose-built monitoring network using Open-Source platforms, IoT technology, and LoRaWAN communications, adhering to World Meteorological Organization guidelines. Additionally, it evaluates two citizen weather observer networks (CWONs): one from a commercial smart device company and another from a global community connecting environmental sensor data. The findings highlight several advantages of bespoke monitoring networks over CWON, including enhanced data accessibility and greater flexibility to meet specific requirements, facilitating adaptability and scalability for future upgrades. However, specialization is crucial for effective deployment and maintenance. Conversely, CWONs face limitations in network uniformity, data shadow zones, and insufficient knowledge of real sensor situations or component characteristics. Furthermore, CWONs exhibit some data inconsistencies in probability distribution and scatter plots during extreme heat periods, as well as improbable UHI temperature values.

The increasing frequency and intensity of heat waves, combined with urban heat islands (UHI), pose significant public health challenges. Implementing low-cost, real-time moni-toring networks with distributed stations within the Smart city framework faces obstacles in transforming urban spaces. However, accurate data is essential for assessing these ef-fects. This paper compares different network types in a medium sized city in West Spain and their implications for UHI identification quality. The study first examines a pur-pose-built monitoring network using Open-Source platforms, IoT technology, and Lo-RaWAN communications, adhering to World Meteorological Organization guidelines. Additionally, it evaluates two citizen weather observer networks (CWON): one from a commercial smart device company and another from a global community connecting en-vironmental sensor data. The findings highlight several advantages of bespoke monitor-ing networks over CWON. These networks offer enhanced data accessibility and greater flexibility to meet specific requirements, facilitating adaptability and scalability for future upgrades. However, specialization is crucial for effective deployment and maintenance. Conversely, CWON faces limitations in network uniformity, data shadow zones, and in-sufficient knowledge of real sensor situations or component characteristics. Furthermore, CWON exhibits some data inconsistencies in probability distribution and scatter plots during extreme heat periods, as well as improbable UHI temperature values.