Notes & Letters

Military applications and meteorological reputations: Franz Baur and the fate of long-range weather forecasting

By Rasmus Wiuff

An accompaniment to the article ‘Was Franz Baur’s infamous long-range weather forecast for the winter of 1941/42 on the Eastern Front really wrong?Bulletin of the American Meteorological Society, January 2023

On 22 June 1941, Hitler began Operation Barbarossa against the Soviet Union with the aim of ending the campaign before winter. The soldiers therefore had no winter equipment, not even in the depots behind the front. The equipment, including guns, rifles and tanks, was not suitable for heavy frost and snow, in contrast to the Soviets’ equipment. In the first few months, the campaign went as planned for the Germans, but then came autumn with rain and mud, the time of year that the Germans call Schlammperiode (mud period) and the Russians more poetically refer to as rasputiza (slush). The Germans faced poor mobility and were stuck for four weeks.

Franz Baur, 1887–1977

The High Command realized that the campaign could not be completed before winter; thus, it was important to know how cold the winter would be. The German meteorologist, Professor Franz Baur, prepared a long-range weather forecast for the winter of 1941-42. During the 1930s, Baur had made a name for himself in the field of long-range weather forecast as the leader of the Research Centre for Long-Range Weather Forecasting (Forschungstelle für langfristige Witterungsvorhersage) in Bad Homburg just north of Frankfurt. The institute became a part of the meteorological service of the German government (Reichsamt für Wetterdienst) attached to the air force (Luftwaffe). Here, Baur and his staff periodically prepared 5 and 10-day forecasts during the summer months from 1932 until the outbreak of the war.

Baur never revealed anything about his forecast for the winter of 1941/42. However, according to an article published ten years after Baur’s death (Neumann and Flohn, 1987) Baur predicted that the winter would be normal or milder than normal, primarily based on the main argument that the previous two winters had been very severe and never in climatic history had more than two severe winters occurred in a row. In early December 1941, the weather suddenly turned unusually cold. Baur’s response to these facts was “[t]he observations must be wrong” (Neumann and Flohn, 1987). The winter ended up being one of the worst on record.

Morning temperatures at Moscow [0700 local solar time (LST)] in late November and the beginning of December 1941 based on data from Neumann and Flohn (1987, p. 621).

Neumann and Flohn’s description of Baur’s wartime activities has no references to original archival material and is probably largely based on Flohn’s memoirs from his years in the weather service. Flohn’s memories are not in favour of Baur’s reputation, which thus suffered a major blow ten years after his death. On Baur’s 125th birthday in 2012, you could read in the German press: “It was his most famous – and probably the most famous wrong prognosis of all time” (Frey, 2012). To date, the description by Neumann and Flohn has been the “authorized” source on Baur’s wartime activities. However, rumours of the wrong prognosis had ruined Baur’s reputation among his colleagues since the war, and he never again got a good job during peacetime. However, based on the original wartime prognoses , which have never been dealt with before, and Baur’s scientific and personal history, my new article shows that this judgment was too harsh and unfair.

Franz Baur’s signature on his infamous long-range weather forecast for the winter of 1941/42 (Baur 1941, p. 3).

About the genesis of the article

Several years ago, I read with great interest the book The weather through 5000 years: The History of Meteorology (Rasmussen, 2010). In it is a longer description of the successful weather forecast for D-Day, but also a brief description of Franz Baur’s failed weather forecast. The argument that after two harsh winters there could not come a third harsh winter puzzled me. I am not a meteorologist, but I have a PhD. in hydrodynamics, and I considered it unlikely that the winter weather would have a “memory” that spanned several years. I have always had a great interest in statistics, and have, among other things, investigated the validity of old Danish weather warnings (articles in Danish) and written a scientific article in an international journal about the persistence of rainy weather (Wiuff, 2020). Franz Baur’s blunder therefore captivated me, and I decided to investigate who he was and, if possible, emulate his calculations. Was he a bad statistician, was he just stubborn, or had he perhaps been a resistance fighter who deliberately made the wrong weather forecast to damage the German troops?

As described in the article, I found out that before the Second World War, Professor Franz Baur was already a controversial meteorologist whom other leading German meteorologists distanced themselves from, finding his methods of long-term forecasting too unscientific. To my surprise, I also found out that he had taught statistics at the University of Frankfurt and written many articles based on statistical methods. In spite of this, I could also document that the argument of no harsh winter after two harsh winters did not hold true. I wrote an abstract to BAMS about my studies, which was the first step before the possibility of a peer-review. The editor thought it sounded exciting and gave the ‘OK’ to move on.

My first draft article relied solely on open sources about and by Baur, plus the statistical analysis. The history editor and one of the two (anonymous) reviewers demanded that if the article was to be considered at all, I should investigate possible previously untreated material in the archives. I had never tried that before, so I almost lost heart. It turned out that there is not a lot of such material from the war, because – as an archivist of the Bundesarchiv, Abteilung Militärarchiv, Freiburg, told me – most of it was destroyed during the withdrawal of the German troops. But luckily, I got in touch with a very helpful librarian at the Deutsche Meteorologische Bibliothek des Deutschen Wetterdienstes (DWD) in Offenbach am Main. Here they hold all of the original forecasts that Baur made during the war – a total of 765 pages. When the librarian heard about Baur’s grim fate after the war, she became very keen to help me. Everything I asked for was quickly photographed and sent to me, but she also found other previously unpublished relevant material. It was a very exciting and fruitful collaboration. From having been a scientific article with a certain historical content, it now also became a historical-scientific article. I am very grateful to the editor of BAMS, the history editor, the anonymous reviewer and the librarian.

My fascination with Franz Baur’s fate may be due to the fact that I feel a certain spiritual kinship with his sometimes foolish eagerness to find connections in the chaotic world of meteorology. If I had been a student with him in the 1920s, I too might have ended up in “bad standing”. But instead, I am pleased to have been able to contribute to a more truthful and fair description of Franz Baur’s professional work, and thereby give him some redress nearly fifty years after his death.


Baur, F., 1941. Temperaturvorhersage für den Winter 1941/42 in Mitteleuropa. Bearbeitet im Forschungsinstitut für langfristige Witterungsvorhersage unter Leitung von Prof. Dr. Franz Baur. 21. Ausfertigung, 5. November 1941, Reihe I G 15. DWD Deutsche Meteorologische Bibliothek, 6 pp.

Frey, A., 2012. Kalt erwischt. Der Meteorologe Franz Baur stellte Hitlers Wehrmacht im Winter vor 70 Jahren eine folgenschwere Wetterprognose. Eine Erinnerung zum 125. Geburtstag.  Frankfurter Allgemeine Sonntagszeitung, Wissenschaft, 12. Februar 2012, Nr. 6. 62.

Neumann, J., and H. Flohn, 1987: Great historical events that were significantly affected by the weather: Part 8, Germany’s war on the Soviet Union, 1941-45. I. Long-range weather Forecasts for 1941-42 and climatological studies. Bull. Amer. Meteor. Soc., 68, No. 6. 620-630.

Rasmussen, E. A., 2010: Vejret gennem 5000 år. English: The weather through 5000 years. Aarhus Universitetsforlag. Danmark. 367 pp.

Wiuff, R., 2020: Analysis and modelling of precipitation intermittency by compound Markov-DARMA models. Water Resour. Res., 56, 1-38.  e2019WR025522.

Wiuff, R., 2023. Was Franz Baur’s Infamous Long-Range Weather Forecast for the Winter of 1941/42 on the Eastern Front Really Wrong? Bull. Amer. Meteor. Soc. 104, No. 1, E107-E125.