The Internet of Things plays a crucial role in various fields, such as smart homes, agriculture, and natural disaster prediction. Data typically needs to be transmitted wirelessly to base stations, with each application having its individual Quality of Service requirements. In this work, we provide a better understanding of the functioning of ESP-NOW at the lower layers and the resulting performance of the protocol under real-world conditions. For this, we conduct experiments under controlled conditions with the widely used Heltec WiFi LoRa 32 V3 board. We further conduct experiments in two typical outdoor environments to assess performance under real-world conditions: farmland under line-of-sight conditions with measurements taken at 21 positions and a forest environment with measurements taken at 205 positions. Special emphasis is placed on the packet delivery ratio and the distribution of delays. Finally, we demonstrate that the delay distributions from the outdoor experiments match a model derived from our experiments on ESP-NOW under controlled conditions.