The Meteorological Observatory Hohenpeißenberg is the oldest mountain weather station in the world. It is located in the municipality of Hohenpeißenberg, about 60 kilometres southwest of Munich, Germany, and at 977 metres above sea level. Meteorological data is collected on the site continuously since 1781.

The measurement series ranks among the longest ever, and was never impacted by urban heat island effects, a problem encountered by the comparably long records from the Basel and Prague observatories.

As of today, it is operated by Deutscher Wetterdienst, and takes part in the Global Atmosphere Watch programme.

In addition to the ozone measurements performed there on a routine basis since 1967, the observatory has also monitored numerous trace gases, aerosols and substances in rain and performed the accompanying scientific process studies since these measurements were started in 1995. Another task is the further development of radar meteorology and its use for the German Weather Radar Network in place since 1967, with the aim of improving both weather forecasting and weather warning.