The conversion of forests alters the microclimate. The entry of polar air masses occurs in South America, but in the Amazon, the effect is different, with temperature drops in winter and convective rains in summer. In this context, the cold surge was characterized in areas with forest, pasture, and urban land cover in the central region of Rondônia state, aiming to understand the phenomena’s behavior in each type of cover. Data from micrometeorological towers of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) were used, with the urban tower located above a building, and the forest and pasture towers at heights of 62m and 8m, respectively. In 2017, a cold surge event was identified, leading to an average reduction of 31% in minimum temperatures across the three cover types. As a characteristic of polar air masses, specific humidity decreased in the affected areas, and frontal rainfall was observed only in the forest. Wind speed doubled, with a predominance of southerly winds. After the passage of the cold surge, the average temperature was restored within three days. Overall, local micrometeorological conditions are altered by the influx of cold and dry air masses, with more significant impacts observed in anthropized areas. However, further studies are needed to assess the influence of land coveron these responses and potential impacts on the population’s livelihood.
