The continuous meteorological observation started on the 1st January 1905. The succession of the meteorological records is one of the longest in the Czech Republic because the Milešovka observatory is the oldest mountain observatory in the Czech territory. At present, the oldest measuring instruments are exhibited at the museum, which is situated directly at the observatory.

From the beginning (1905) till 1957, the observations were carried out three times a day (at 7, 14 and 21 hours UTC). On the 1st July 1957 a continuous twenty four-hour service was established. It allowed three-hour synoptic observations for the meteorological service (at 0, 3, 6, 9, 12, 15, 18 and 21 hours UTC). One-hour measurements have been performed since 1998.

In July 1998, the automatic meteorological "Vaisala" station was installed at the Milešovka observatory. The system of sensors measures air-temperature and humidity, air pressure, visibility, wind velocity and wind direction, soil-temperature in the depths of 5, 10, 20, 50 and 100 cm, precipitation amount, sunshine duration, and cloud height automatically. The observers determine furthermore cloud amount, cloud type, weather situation, depth of snow cover and many other meteorological characteristics.

Apart from standard meteorological and climatological observations, a number of specially designed experiments are carried out at the Milešovka observatory. Many of them provide data inputs for research projects of the Institute of Atmospheric Physics (IAP ASCR). At present, most of them are related to the physical and chemical properties of fogs, low-level clouds and precipitation in which the pollutant content is taking into account.