Based on real-time field data from tropical outdoor microcellular networks (Akure, Nigeria), this study investigates the propagation of high-capacity millimeter waves ( mmWave) in the 30-100 GHz frequency range. The data covers simultaneous measurements of rainfall rate and received signal strength (RSS) over a 300-meter path length between a Communication Research Lab (CRL) in FUTA Nigeria and the National Television Authority Tower at Iju Akure Nigeria at one-minute sampling time over a year (Jan 2021–Dec 2021). The study investigates the average network availability derived from the real-time data of rain rates. It compares the distributions of the measured rain-induced attenuation at various times of signal unavailability for 30 GHz with the modified anticipated attenuation by the Synthetic Storm Techniques (SST) model. Using MATLAB software and the most recent NYUSIM channel model software package (Version 3.1), an investigation of important propagation channel characteristics such as route loss, fade margin, and received power during heavy rains was also conducted. Based on convective and stratiform rain types, the focus on the propagation characteristics of a typical network provider, a Mobile Telecommunication Network (MTN), was assessed power obtained at the receiving end, signal loss along the route, and the interval of signal fading. The results show that the modified SST model provides high consistency with the measured attenuation through the outdoor links. The signal loss of about 80 dB is needed to be compensated as the rain rates approach 140 mm/hr over the 300-meter path length. The study also demonstrates that for multidirectional and oriented directional antenna links, regardless of the fading due to rain, the NYUSIM platform model provides a better representation of the power delay profile. The research outcome will provide useful information for setting up fifth-generation (5G) and other future wireless networks for outdoor applications, especially in tropical areas.