We describe the use of a translation memory in the context of a reconstruction of a landmark application of machine translation, the Canadian English to French weather report translation system. This system, which has been in operation for more than 20 years, was developed using a classical symbolic approach. We describe our experiment in developing an alternative approach based on the analysis of hundreds of thousands of weather reports. We show that it is possible to obtain excellent translations using translation memory techniques and we analyze the kinds of translation errors that are induced by this approach.