Reliable, localized environmental data acquisition is essential for microclimate tracking, agricultural planning, and urban sustainability. This paper presents the end-to-end design, implementation, and rigorous characterization of an autonomous, low-power Internet of Things (IoT) weather station. The system integrates digital ambient sensors—specifically measuring temperature ( ), relative humidity ( ), and atmospheric pressure ( )—interfaced to an ESP32 microcontroller via I2C and SPI communication buses. Sensor calibration is achieved through empirical curve fitting against calibrated laboratory standards. Acquired telemetry is transmitted using the lightweight MQTT protocol over Wi-Fi to a cloud-based dashboard and local non-volatile storage for time-series logging. Experimental results demonstrate an absolute temperature accuracy of  , relative humidity accuracy of  , and pressure drift of less than  . The realized framework establishes a reproducible template for real-time, community-level environmental resilience and resource management.