In recent years, Wireless Sensor Networks (WSNs) have been used widely due to their important roles in the Internet of Things (IoT) era. They provide a communication infrastructure to collect, transmit and exchange sensory data in varied IoT applications. Besides their advantages, WSNs have to overcome some challenges such as short network lifetime and the vulnerability of WSNs to uncertain environmental conditions. LEACH is one of the most famous clustering mechanisms to prolong a network lifetime by electing a cluster head based on a probability model. This paper proposes a novel clustering scheme based on LEACH protocol to adapt uncertain network conditions. The proposed Medium Access Control aware LEACH (MAC-LEACH) based on Fuzzy logic brings energy efficiency of wireless sensor networks in reasonable complexity.