We introduce a simple and effective method to test for temperature persistence on a range of time scales. Daily temperatures for three regions are examined: Central England, El-Nino region and global. On time scales of less than a year, climate model simulations reproduce the observed high persistence in all regions. However, for longer time scales the climate model systematically underestimates the persistence of global mean temperatures. The anti-persistence in the El-Nino region is well simulated by the model. Scaling behavior is seen for Central England temperatures but is not reproduced by the model. Some of these discrepancies may be accounted for by insufficient ocean-atmosphere coupling. ¿ 2001 American Geophysical Union