In the north people will be wondering where the heat is this weekend.

Sweater weather prevails, especially at the lake, the wind blows quite rough - and now and then there are showers.

The flair there is more reminiscent of a friendly autumn than an overheated summer, but that doesn't have to be a mistake.

Great heat is brutal and dangerous, and not a condition one would wish to endure for long.

Andrew Frey

Freelance author in the science section of the Frankfurter Allgemeine Sunday newspaper.

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That's the good news just before the start of the weekend: The brutal, murderous heat that was supposed to haunt us this weekend is long gone.

Luckily, Cologne does not reach 45 degrees and neither does 43 degrees in Frankfurt, the thermometer will not even exceed the 30 degree mark this weekend, at most on the Upper Rhine it is enough for a hot day with temperatures just over 30 degrees.

Overheated calculation by the American weather service

Almost 15 degrees less than predicted, what's the matter with the meteorologists?

Actually nothing, most did their job properly, but a single, completely overheated main run of the Global Forecast System (GFS) of the American weather service from last Saturday, which flows unfiltered and directly into the free weather apps, was enough to get the whole thing country reeling in a heat hype.

Not only the social networks ran hot and provided the fuel that is needed for such a wildfire of headlines, but also the media and some television meteorologists fueled the topic of conversation all too readily.

It would have been easy to see through the prognosis with a cool head.

There were enough indications: Forecasts over a period of one week are uncertain and should therefore be interpreted very cautiously.

The other weather models also did not follow suit that Saturday and delivered lower values.

In addition, the main run of the GFS, which transplanted the 45 degrees to Cologne, was an outlier, as a look at the so-called ensembles showed.

These are calculations with slightly different initial conditions to assess the reliability of the main run forecast.

And finally, meteorologists like the weather model developer Janek Zimmer from kachelmannwetter.com quickly spoke up on Twitter, who cast doubt on the overheated run.

It has long been known to experts

that the American weather model has problems with soil moisture.

There, the floors in the model world dry out much faster than the real floors do in reality.

And it makes the drying out of the soil with almost zero percent moisture in the end even completely unrealistic. Every meteorologist knows that soils in Europe do not dry out completely.

The GFS main run was therefore a temperature forecast error.

The heat comes anyway

All that is left of the extreme heat is extreme hype, and a new record value is a long way off for the time being.

And yet the country is facing an extraordinarily hot weather period. From Monday onwards, all weather models indicate a push of very hot air towards Central Europe.

"This heat is dry," says Marcel Schmid, meteorologist at the German Weather Service in Offenbach, although it is unclear how far it will penetrate the country and how long it will last.

A longer heat wave is quite likely in the south-west, but not so in the north-east.

At the beginning of the week, the meteorologist expects highs of more than 35 degrees on the Upper Rhine, and by Wednesday the Iberian hot air could flood the whole country.

Values ​​of 38 degrees are then possible in the hotspots on the Rhine, Main and Moselle, but it is still difficult to assess whether it will also be 40 degrees, says Schmid.

However, the imminent heat wave should not be underestimated.

In some regions, the heat stress will be extremely high during the day and night for several days.