The results of the research into impacts of extremely cold climates on physical and mechanical properties of basalt plastic rods of a periodic profile have been given. The object of research is a polymer composite building purpose material - basalt composite reinforcement, constituting one-way-polar basalt rods with deformed section diameter from 6 to 8mm., made on the basis of LLC "TBM" production unit with technical production line "Struna" under the technical specifications 2296-001-86166796-2013 "Non-metallic composite basalt reinforcement". Changes of physical and mechanical properties have been defined for the initial and exposed samples of basalt plastic reinforcement. After exposure in Yakutsk, the increase in strength properties by 4–12% depending on the diameter of rods has been revealed. The research of temperature dependences of the samples of basalt plastic reinforcement has showed rather good reproducibility of the results obtained by different methods. The observed increase in Tg, ∆L⁄L0 and ᾱ is due to the prevalence of the effect of post-hardening of the BPA polymeric matrix over the effect of tension relief of the polymeric matrix at the interface with basalt fiber.Thus, as the result of the conducted research, the increase in adhesion strength of the “fiber- matrix” compounds in the process of exposure has been established, and the matrix added solidity to the material and facilitated effective usage of mechanical properties of fibers and uniform distribution of efforts between them.