Variations in human subsistence and settlement patterns have been documented at Holocene archaeological sites across Island and Mainland Southeast Asia. Although climate is frequently invoked as a causal mechanism underlying this variation, direct evidence of ancient rainfall variability on the scale of human lifetimes has thus far been elusive. Here we use a novel time-resolute method for in situ measurement of human tooth enamel δ¹⁸O values (n = 2629 near-weekly measurements sampling 51 years) to assess past rainfall seasonality patterns in Southeast Asia. Seasonal fluctuations in enamel δ¹⁸O values of ancient humans from several different periods are compared to modern rainfall recorded in Vietnam, Philippines, and Indonesia by the Global Network in Isotopes in Precipitation (GNIP). The likelihood that the ancient humans reflect local precipitation patterns is established through measurement of bulk enamel ⁸⁷Sr/⁸⁶Sr ratios. Comparison of the archaeological individuals and the modern rainfall datasets shows that the seasonal variabilities in ancient δ¹⁸O_enamel are consistent with seasonal variabilities in modern δ¹⁸O_precip across the study locations (highest in Vietnam, lowest in Indonesia, intermediate in the Philippines). Strong seasonal δ¹⁸O_enamel trends in four of five hunter-gatherers from Con Co Ngua, Vietnam, facilitate the inference of birth approximately six months prior to the onset of monsoons, consistent with tropical subsistence societies where food availability correlates with rainfall. High-resolution analysis of human tooth enamel represents a powerful new tool for seasonality reconstructions across different regional and climatic settings.

东南亚岛屿和大陆的全新世考古遗址记录了人类生存和定居模式的变化。尽管气候经常被认为是这种变化背后的因果机制，但迄今为止，人类寿命范围内古代降雨量变化的直接证据仍然难以捉摸。在这里，我们使用一种新颖的时间分辨方法对人类牙釉质δ ^{18 O 值进行}原位测量（n = 51 年采样的 2629 次近每周测量值），以评估东南亚过去的降雨季节性模式。全球降水同位素网络 (GNIP) 将几个不同时期的古代人类牙釉质δ ¹⁸ O 值的季节性波动与越南、菲律宾和印度尼西亚记录的现代降雨量进行了比较。古代人类反映当地降水模式的可能性是通过测量大块牙釉质⁸⁷ Sr/ ⁸⁶ Sr 比率来确定的。考古个体和现代降雨数据集的比较表明，古代δ ¹⁸ O_{釉质的季节变化与研究地点现代}δ ¹⁸ O_降水的季节变化一致（越南最高，印度尼西亚最低，菲律宾中等） 。越南 Con Co Ngua 的五名狩猎采集者中，有四名具有强烈的季节性δ ¹⁸ O_牙釉质趋势，有助于推断在季风爆发前大约六个月出生，这与粮食供应与降雨量相关的热带自给社会一致。对人类牙釉质的高分辨率分析代表了跨不同区域和气候环境的季节性重建的强大新工具。