We propose a compact road weather sensor node to predict the road surface temperature. This node is based on the model of the environment and temperature of roads (METRo) developed by the Government of Canada. The model requires an atmospheric forecast, the station configuration, and observation information as inputs. Observation data have commonly been produced by a road weather information system (RWIS), but this system is larger than necessary, and it has been difficult to maintain the surface sensors embedded on roads. We experimentally determined that the air and surface temperatures are key parameters for the model to predict the surface temperature. The proposed node was designed to be compact with an integrated environmental sensor for measuring atmospheric parameters and an infrared (IR) non-contact thermometer to obtain the surface temperature. In field tests with the prototype, we verified the good observation performance of the IR remote sensor by using a standard instrument for measuring the surface temperature. The results of the model based on data obtained by the prototype also showed excellent predictive performance during nighttime. This weather sensor node uses long range (LoRa) technology, which makes it suitable for long-range, low-power, and low-data-rate performance, suggesting the possibility of its commercialization.