The climate change is a natural phenomenon and effect on atmospheric which is the media of wireless communication. For the high performance in the telecommunication system this study therefore aimed to study the variables affecting to signal strength of wireless networks. The values of temperature humidity pressure and the signal strength of wireless networks 5 GHz were measured. The sample of this study was 148 access-points of TOT in Yasothon Province. For statistical analyses Pearsons correlation and regression were employed. The findings revealed that: 1) the average level of signal strength was 69.44 –dBm. The average levels of temperature humidity and pressure were 28.085 ?C 73.145% and 1004.246 hPa respectively 2) variables that had great influences on signal strength of wireless networks consisted of temperature humidity and pressure and 3) ambient variables of temperature humidity and pressure could predict the level of signal strength at 76.8%