Autumn surprise: extreme heat and record-breaking rain in September!

Autumn surprise: extreme heat and record-breaking rain in September!

In September 2024, the German Weather Service (DWD) once again put Germany's climatic challenges to the test. While the first part of the month was characterized by mid-summer temperature fluctuations, unforeseen weather changes followed that significantly changed the weather pattern. Unusual amounts of precipitation and temperature fluctuations as well as heavy snowfalls in the Alps created special conditions.

Temperatures in September averaged 15.3 degrees Celsius (°C), an increase of 2 degrees compared to the international reference period of 1961 to 1990. But that's not the only thing that made this September notable. A heat wave was recorded in the northeast in the first week of the month, culminating in Doberlug-Kirchhain on September 4th at 35.2 °C. But while temperatures broke records at the beginning of the month, the weather became significantly cooler around the middle of the month, which promptly led to frosty nights in many places.

The influence of the storm ANETT

A decisive factor in the weather fluctuations was the storm ANETT, which brought heavy rainfall, particularly in the south and east of Germany. The precipitation measurements showed that around 107 l/m² of precipitation was measured in September, which corresponds to around 175 percent of the normal value for the reference period 1961 to 1990. Berchtesgadener Land was particularly affected, where there was extreme rainfall of up to 500 l/m² - more than three times as much as usual.

In addition, there was significant snowfall in the Alps, in a month that was supposed to mark the transition to autumn. On September 13th, Ruhpolding-Seehaus reported the highest daily rainfall in Germany for this year at 156.8 l/m². These extreme weather events also led to the risk of flooding on the Oder, which developed from rainfall in the Czech Republic and Poland.

A mixed weather picture

Despite the massive rainfall, the sun shone above average in Germany. With almost 177 hours of sunshine, the sunshine duration significantly exceeded the average values. Particularly in the northeast, especially on the Baltic Sea, the sun shone for up to 230 hours, while in the southwest it was only sunny for around 130 hours. These differences highlight how inconsistent weather conditions can be in just one month.

Saxony-Anhalt also experienced a sharp change in weather. At the beginning of the month, up to seven days were recorded with maximum temperatures above 30°C. Drewitz in Jerichower Land set a new September record for Saxony-Anhalt on September 4th with 34.6 °C. But here too, the change in the weather on September 13th resulted in cooler temperatures before the autumnal character of the month finally took hold.

Overall, September 2024 shows how drastically weather conditions can vary and what challenges they pose for the DWD's measurement technology and analyses. The climatic conditions, both warm and wet, make it clear that autumn is on its way to taking over, and with full force.

The causes and effects of these weather phenomena are of interest not only to meteorologists, but also to everyone concerned with climate issues. In its initial evaluations at around 2,000 measuring stations, the DWD came to the conclusion that September once again proved that weather is not only predictable, but can also remain surprising. More detailed information and further details about the weather conditions in September can be found in the report www.hallanzeiger.de be read.