Summary In order to estimate experimentally the intensity and amplitude of thermal shocks during and after excavation, we monitored temperatures of archaeological bones on the field at three Syrian sites of the arid steppe, Qaramel, Dja'de and Aswad. Water cleaning and sun drying appear to be the most damaging steps, with temperature variations of ca. 11,000 °C/h and 84 °C/h, respectively. Ancient DNA (aDNA) bone samples kept between −7 and +12 °C from their extraction to the lab suffered much lower thermal variations (6 °C/h). Estimation of the temperature variations at different depths in the soil suggests that aDNA has suffered negative thermal conditions shortly after burial and again during excavation, before their extraction by archaeologists.