Analysis of ERA40 temperature and accumulation data suggests that annual mean isotopic fluctuations due to temperature change will be geographically very variable across the Peninsula: isotopic variations of 0.4 parts per thousand at James Ross Island; 0.9 parts per thousand at Dyer; and 1.3 parts per thousand at Gomez are all likely to indicate an identical magnitude of temperature change. The reduction in the magnitude of the isotopic signal in the north and east is due to climatically dependent synoptic covariance between temperature and accumulation; whilst in the west and south seasonal covariance amplifies the isotopic temperature signal. Additionally we show that the relationship between accumulation and temperature is rather weak in the north-east regions but is stronger in the central and southerly regions. Therefore isotopes may record 11% to 30% of the variance in annual mean temperatures in the north east; 75% in central regions; and 70% in the south. This study enables physically based reconstructions of Peninsula climate based on multi-core analysis. Citation: Sime, L. C., G. J. Marshall, R. Mulvaney, and E. R. Thomas ( 2009), Interpreting temperature information from ice cores along the Antarctic Peninsula: ERA40 analysis, Geophys. Res. Lett., 36, L18801, doi:10.1029/2009GL038982.