Tim Palmer (1952-), theoretical physicist and meteorologist, has led the development in Britain of probabilistic (rather than the more familiar deterministic) weather and climate forecasting using computer models, at the Meteorological Office and the European Centre for Medium Range Weather Forecasting. He joined the Met Office in 1978 following a DPhil in general relativity theory. His research into the predictabilityand dynamics of weather and climate on the one hand, and into relations between quantum theory and gravity theory on the other, is linked by an interest in systems that are ‘nonlinear’. With Michael McIntyre he produced visualisations of the biggest breaking waves on Earth (in the stratosphere) and his ‘invariant set postulate’ aims to solve problems in quantum mechanics through fractal geometry. Tim is currently a Royal Society 2010 Anniversary Research Professor of Climate Physics, in the Department of Physics, University of Oxford.