The climate we live in affects our lives in profound ways: hot summers, cold winters, dry spells and wet weather all leave their mark. For growing children, one way seasons and storms are recorded is in their teeth. As we have shown in new research, teeth contain a week-by-week climatic history of their owner’s childhood. To establish this, we studied the teeth of wild chimpanzees, captive macaque monkeys, and a woman born in Brisbane in January 1990.