Record: “We experienced the hottest September in the 257 year history of measurements” 5 minutes

Published September 30, 2023, 11:45 am

September 2023 brought stable high pressure weather for almost the entire period. This meant it was extremely hot, dry and sunny. “We are experiencing the hottest September in the 257-year history of measurements”, says climatologist Alexandre Orlik from GeoSphere Austria. “September 2023 was 3.2 degrees above the average for the 1991 to 2020 climate period in the Austrian lowlands and 4.2 degrees in the mountains.”

Second sunniest September since 1925

Compared to the 1961-1990 climate period, September 2023 was 3.6 degrees above average in the lowlands and 4.2 degrees above average in the mountains. The number of hours of sunshine was also exceptionally high. “Across Austria, the sun shone 40% longer in September 2023 than in an average September,” says climatologist Orlik. “This made this the second sunniest September since sunlight measurements began in 1925. Only September 1997 was sunnier, with a 55 percent increase.”

Little precipitation

In the Austrian-scale assessment, September 2023 brought 45 percent less precipitation than an average September. This places it among the 20 driest Septembers in measurement history. The final classification can only be said after all measuring stations have been evaluated at the end of the month. September 2023 was a far cry from the extremely dry months of September 1865 (-82 percent), 1959 (-73 percent) and 1947 (-72 percent).

Extraordinarily many summer days

On September 9, 2023, it was warmer in many of Austria’s mountains than it had ever been in September since measurements began. For example, 13.0 degrees were measured at the Sonnblick Observatory (3,109 meters above sea level) on September 9th. The previous September record was 12.4 degrees in 1997. Measurements have been made in Sonnblick since 1886. In Brenner (1,412 m above sea level) 27.5 degrees were measured on September 10th. The previous September record was 26.6 degrees in 2006. Measurements have been taken in the Brenner since 1948. The number of summer days in September 2023 was also extreme (at least 25 degrees). New records were reached in some capitals.

© GeoSphere Austria