The audible noise generated by UHV AC transmission lines includes broadband noise and "100 Hz" pure tone. Because of the reflection on the earth

the standing wave of the pure tone is generated. We investigated the influences of weather factors on the pure tone of UHV transmission lines

and proposed a pure tone prediction model based on weather factors. The correlation between rainfall

temperature

wind speed

atmospheric pressure

humidity and pure tone was analyzed by using the pure tone and weather parameters monitored by a long-term observation station for the electromagnetic environment of UHV transmission lines. Two prediction models of pure tone in rainy and rainless weather were established by the multi-layer perceptron and LM（Levenberg-Marquardt） algorithm. The models were trained by the data of the selected monitoring station. The prediction results show that the influential weight to the pure sound from high to low is rainfall

wind speed

atmospheric pressure

temperature

and humidity. The root mean square errors of the prediction results obtained by two prediction models are 2.032 dB and 3.363 6 dB

respectively. The results can provide a technical reference for the suppression of "100 Hz" pure sound of UHV AC transmission lines.