Pilot-Project: Wettermanufaktur presents Corona-Weather-Index

Berlin, 25 March 2020. Wettermanufaktur starts the pilot project Corona-Weather-Index. From now on the private weather service provider offers a 7-day forecast on the possible weather-related spread of COVID-19 disease for Europe and the United States of America on its website

At the beginning of March the research paper "High Temperature and High Humidity Reduce the Transmission of COVID-19" was published on the Social Science Research Network. Its authors conclude that high temperature and high relative humidity in summer could effectively reduce the transmission of COVID-19 disease. The researchers calculated the daily effective reproduction rate R for 100 Chinese cities in which more than 40 cases of COVID-19 disease occurred in the period from 21 to 23 January 2020. This figure indicates the severity of infectiousness.

The team of Wettermanufaktur has taken up this approach and developed a so-called Corona-Weather-Index. The activity and behaviour of COVID-19 under different climatic conditions has hardly been researched so far. The index is a pilot project and could be a useful early indicator of when, from a meteorological point of view, the peak of the epidemic may be expected to be delayed or even flattened. The calculation of the index is based on forecasts of air temperature (°C) and relative humidity (%) from various weather models, such as the European Centre for Medium-Range Weather Forecasts.

The index is available as a 7-day forecast for Europe and the United States of America on the website The maps are provided once a day at 12 am UTC and are updated continuously. The four-level index scale comprises the rating 1 = low transmission risk, 2 = moderate transmission risk, 3 = high transmission risk and 4 = very high transmission risk.

Regardless of the forecasts presented on, the specifications and instructions of the respective competent authorities must be followed.


Wang, Jingyuan and Tang, Ke and Feng, Kai and Lv, Weifeng, High Temperature and High Humidity Reduce the Transmission of COVID-19 (9. März 2020). Available at or


Forecast for Europe (27 March 2020) and the United States of America (28 March 2020)