If it rains on 25th November, the national average is almost 0.8 degrees colder at Christmas – this is revealed by the results of the analysis carried out by Starschema. The data scientists of the largest Hungarian data analysis company examined the accuracy of one of the most well-known folk beliefs using data from the past 100 years. According to statistics, based on yesterday morning’s temperature readings, there is more than an 84 percent chance that we will have a frosty Christmas in most parts of the country.
If it rains on 25th November, Christmas will be frosty – so says one of the most famous Hungarian folk observations related to the weather, the reverse of which is also considered true (“If it is frosty on 25th November, Christmas will be rainy”). This means that if the daily minimum temperature is above 0 degrees on November 25th, we can expect colder weather on Christmas Day, i.e. it will freeze (and vice versa). The weather data of the last 100 years (source: OMSZ Meteorological Database) show that the observation is confirmed more often than not. This was the result of data scientists from the largest Hungarian data analysis company, Starschema, who examined the daily minimum temperature values of 10 cities (Budapest, Debrecen, Keszthely, Miskolc, Nyíregyháza, Pécs, Sopron, Szeged, Szombathely, Túrkeve). According to their calculations, “Katalin’s prediction” was fulfilled in nearly 69 percent of the cases: when the weather was mild on November 25th, it froze on at least one day of Christmas; when it froze on November 25th, temperatures above 0 degrees were measured on at least one day of Christmas.
The observation is most accurate when it rains on 25th November: based on the data of the last 100 years, there is a national average of more than 84 percent chance that we are facing a frosty Christmas period. On the other hand, if it freezes on 25th November, there is a 51.4 percent chance of a milder Christmas. It is interesting that among the examined cities, it is in Budapest that the most observations are confirmed. In the capital, this observations predicted correctly 78 times out of the last 100 years. From this point of view, Szeged (73), Nyíregyháza (71) and Pécs (71) also performed well, while the same value for Túrkeve, which is at the bottom of the list of ten, is only 64. The average temperature data for the Christmas period (December 24th-26th) also support the correctness of popular observations. Examining the daily minimum values, the national average is almost 0.8 degrees colder in the years when it rains on 25th November. In this area, too, the prediction comes true best in Budapest: in the capital, on average, approx. It is 2.4 degrees colder between December 24th and 26th after a mild November 25th. In the case of Nyíregyháza, which is in second place on the list, this value is 1.64, while in Miskolc, which is third, it is 1.16 degrees.
In the examined period, there were only two years when the observations failed completely. In 1948 and 1953, the prediction was not fulfilled in any of the 10 investigated cities, as it froze everywhere on November 25th and Christmas. Based on yesterday morning’s temperature data, it can be stated that it was raining in the majority of the country, so based on her forecast, we can expect a frosty Christmas this year. The thermometers measured values above 0 degrees in all but 3 of the 10 cities examined. In Keszthely, Szeged and Szombathely, the morning minimum temperature was around 0 degrees.