The Amazon biome is influenced by El Niño event, which reduce precipitation and increase temperature. However, little is known about its effects on tree formation dynamics in this region. Here, we evaluated the effects of local (precipitation, temperature, and solar insolation) and large-scale (El Niño) climatic variables on wood traits of Tectona grandis (teak) in the Amazon. Discs were collected from the base of trees aged 12 years and used for anatomical and physical analyses. We evaluated three periods (i.e., pre-El Niño (2012/2013), El Niño (2014/2015), and post-El Niño (2016/2017)). Wood density, vessels, and rays were compared to local and large-scale climatic variables. The extreme drought caused by El Niño event reduced the width and length of teak vessels. Additionally, precipitation during some months of the year increased vessel size and wood density. In some months of the year, ambient temperature reduced vessel width and length. Moreover, the effect of solar insolation depended on soil moisture availability. Thus, our results provided clear evidence of teak acclimatization to El Niño in the Amazon region and should promote further studies on tree responses to climate.