The investigation of historical archives made possible the reconstruction of past climate before official instrumental measurements started (c. 1880). These archives consisted of weather descriptions and diaries, information about the wine harvest and other agricultural products, as well as their price fluctuations. Based on this data, it was possible to calculate meteorological parameters and to create an index of temperature and precipitation values. By contrast with regular proxy data like tree rings or ice cores, historical sources have the advantage to reconstruct the climate in a very high resolution. The limitation of historical data is that they reach only ca. 1000 years into the past. This paper shows a climate reconstruction of the Upper Rhine Valley using several historical sources and a minimum resolution of a monthly reconstruction from the years 1483 to 2005.