25 degrees in various places, regional September heat wave a fact

NOS weather photo / Erica van Leeuwen-de BruijnBlue sky and a palm tree in Goes

NOS Nieuws•vandaag, 13:27

An unexpectedly warm late summer has resulted in a new record this week. In Hoek van Holland it was more than 25 degrees for several days, making a rare regional September heat wave a fact, reports Weerplaza.

Since Monday it has been 25 degrees or warmer in Hoek van Holland. On three days the mercury rose to 30 degrees, which could be called an unofficial local heat wave. It is only the seventh time since weather measurements began that a regional heat wave has been observed in September, Weerplaza reports.

In Gilze-Rijen and Eindhoven it is also “a matter of time” before such a regional heat wave is recorded. Warm temperatures are also expected there in the coming days.

Earlier this year, regional heat waves were already detected at various measuring points, but this happened in the summer months of June and July. That was in Ell, Arcen, Eindhoven, Volkel and Maastricht where it was warmer than 25 degrees for several days. Such regional peaks are much more exceptional in September, says Weerplaza. “Tropical days are rare in September and this especially applies to heat waves.” The last regional heat wave in September was in 2016.

It is not yet possible to say whether there will be a national heat wave this week. To this end, the KNMI looks at the national measuring point in De Bilt, where 26 degrees are currently measured. Tomorrow a maximum temperature of 29 degrees is expected in De Bilt, the day after tomorrow 30. It’s all about tension, concludes the KNMI, which further emphasizes that the institute only speaks of national heat waves, not regional ones.

In order to qualify as a heat wave, it must reach 25 degrees or more on at least five days and the mercury must rise to 30 degrees or more on three days.

Warmest summer ever recorded

The KNMI points out that September – like all other months – has become warmer since the beginning of the last century. The temperature in September is now even slightly higher than the temperature in June at the beginning of the last century. The number of summer days in September – where it is warmer than 25 degrees – is also comparable to the June month of the early last century. This makes September de facto the new June, the institute says.

Last week, the World Meteorological Organization and Copernicus, the European Union’s climate agency, reported that the summer of 2023 was the warmest summer on record worldwide. The average temperature on earth in the months of June, July and August was 16.77 degrees, which is 0.66 degrees higher than the average in the years 1991 to 2020.

The scientists from the EU climate agency explicitly point to the combustion of coal, oil and natural gas, among other things. El Niño, a temporary warming of parts of the Pacific Ocean, also contributed to the warm summer.

The heat caused problems in several countries. For example, forests and wildfires broke out on a large scale in Southern Europe, Canada and the northwest of the United States as a result of the heat and drought.