## 5 Conclusions  
The evaluation of the biofthermal heating effect on human skin is crucial for the application of MMW/sub-THz waves in future wireless communications and biological weapon scenarios in outdoor environments. In this study, we extensively investigate the efficiency of MMW/sub-THz waves for biofthermal heating under outdoor weather conditions, considering the challenges posed by water vapor and falling rain. To accomplish this, we propose a comprehensive theoretical model that incorporates [PERSON] bioheat transfer equation (BHTE), the Mie scattering theory, and the ITU-R model. The proposed model is validated using measured data and is found to accurately evaluate the heating effect. We systematically explore the impact of various factors, including water vapor humidity, rainfall rate, propagation distance, operating frequency, illumination time, and power density, on the biofthermal heating effect. We observed that the heat transfer coefficient is highly sensitive to the temperature differences between the skin and the surrounding environment. In the presence of falling rain, the thermal heating effect of MMW/sub-THz waves is diminished due to the formation of a water layer on the skin surface. However, this water layer does not cause significant channel propagation losses when the distance between the power source and the target (skin) is limited.  
It is important to note that our work has been validated by measurements conducted on rat skin, and the propagation models employed in our analysis have been widely justified. Although there are certain assumptions in our study with limited justifications, the persuasive nature of this work lies in the validation of the thermal heating model using rat skin measurements and the extensive justification of the propagation models. Consequently, we are confident in the reliability and validity of our findings.  
In conclusion, this work confirms the current and near-future applications of sub-THz frequencies in biofthermal heating. The developed theoretical model, validated by rat skin measurements, is also deemed suitable for evaluating in vitro-in vivo terahertz communication channels.  
Conceptualization, J.M.; methodology, M.W., P.L. and J.M.; software, M.W. and P.L.; validation, M.W., investigation, M.W., P.L. and Y.L.; writing--original draft preparation, M.W.; writing--review and editing, J.M. and X.B.; supervision, J.M.; project administration, J.M.; funding acquisition, J.M. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was supported in part by the National Natural Science Foundation of China (62071046), the Graduate Innovative Practice Project of Tangshan Research Institute, BIT (TSDZX202201), the Science and Technology Innovation Program of Beijing Institute of Technology (2022 CX01023) and the Talent Support Program of Beijing Institute of Technology \"Special Young Scholars\" (3050011182153).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** We appreciate the support from [PERSON] from the Beijing Institute of Technology.  
**Conflicts of Interest:** The authors declare no conflict of interest.