Quality controlled and gap-filled continuous atmospheric visibility data (Meteorological Observable Range MOR) measured at the urban rooftop weather station at Freiburg-Chemiehochhaus (FRCHEM, 7.8486ºE, 48.0011ºN, 323.5 m) using an a forward scatter system (CS125, Present Weather and Visibility sensor, Campbell Scientific Inc.) operated 2 m above roof level. Quality controlled atmospheric visibility data are available and aggregated at 10min, 30min, hourly, daily, monthly and yearly resolution for the year 2024. Average, minimum and maximum visibility are provided on hourly, daily, monthly and annual scales. Hours and days with at least one minute of a visibility of less than 20, 10, 4, 2, 1, 0.5 and 0.2 km based on the WMO classes are provided on daily, monthly and annual scales. Can be used to determine frequency of fog conditions. Hours and days with at least one minute of a visibility of greater than 50 km are provided on daily, monthly and annual scales. Maximum visibility output by the CS125 is 75 km, so a value of 75 km means greater or equal 75 km. Averaged visibility accounts for values greater than 75 km with 75 km. Detailed information on gap-filled data is provided. Note: All times are provided in UTC, not local time. For more details read `FRCHEM_2024_Visibility_MetaData.txt`.

COPYRIGHT Creative Commons Attribution 4.0 International. Copyright Albert-Ludwigs-Universität Freiburg, Professur für Umweltmeteorologie, Werthmannstrasse 10, Freiburg, Germany. CREATOR This work is owned by the University of Freiburg. ATTRIBUTION The [creation and] curation of this work has been supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 855005) and the University of Freiburg. DISCLAIMER The use of the work is at the user's own risk. The authors, the University of Freiburg, and/or the European Research Council accept no liability for material or non-material damage arising from the use or non-use or from the use of incorrect or incomplete information in this work. The authors, the University of Freiburg and/or the European Research Council are not responsible for any use that may be made of the information in this work. The legal provisions remain unaffected.