Sources of fire, midday heat, ventilation: Twelve heat myths in a fact check

The heat wave is not only causing fiery discussions on social networks.

Sources of fire, midday heat, ventilation: Twelve heat myths in a fact check

The heat wave is not only causing fiery discussions on social networks. Many claims are made: there is no sunburn in the shade, extreme temperatures trigger forest fires and values ​​of 40 degrees are normal in Germany. But is that even true?

40 degrees in summer are normal in Germany

In the past few days, the 40-degree mark has been used in the weather reports in an almost inflationary manner. This is of course due to the forecasts of the weather computers, with which the forecasts could tell us that 40 degrees is quite normal in Germany. The same applies to social media comments such as "Summer at last - heat at last". 40 degrees in Germany are anything but normal.

The 40-degree mark is a sound barrier that was officially exceeded in German weather history for the first time in 1983. Namely on July 27, 1983 in Gärmersdorf, Bavaria, with 40.2 degrees. Then there was another long break before the extreme heat hit Germany several times with new records from the depths of the Sahara - namely in 2015 with 40.3 degrees and then again in July 2019 with peaks of up to 40.5 degrees July 24 and over 41 degrees on July 25, 2019.

It is hottest at midday ("midday heat")

Incidentally, the highest temperatures of the day are not reached in the so-called midday heat, but usually only in the afternoon. Unless there is a thunderstorm or an air mass change in between. A shift in the wind, for example on the coast, can also mean that the temperature peaks earlier. But that is rather rare.

You don't get sunburned in the shade

Even in the shade, bathing in the sun is not entirely harmless. Around a third of ultraviolet radiation arrives in the shade on the skin. In any case, sun protection with sun creams is still necessary, especially for sensitive skin types and children.

Summers should be dry and hot

Here, too, social networks and the opinions expressed often convey a wrong picture of summer. The months from May to August in particular are characterized by high rainfall in our latitudes. This is due to the fact that the air is warm and can therefore transport a lot of moisture - an ideal basis for summer thunderstorms with corresponding amounts of rain. On average, around 70 to 80 liters per square meter per month fall in the summer months, while in winter it is more around 50 to 60 liters.

Heat triggers forest fires

If heat were actually responsible for fires, then it would easily have to be around 300 to 400 degrees. However, the highest temperatures ever measured on earth are in the range of around 55 degrees. That's not nearly enough - even if these temperatures are measured in the shade and at a height of two meters. Higher values ​​are possible on the ground and in the sun. But even those are far too small to start a fire.

Fire from discarded glass bottles

Although it cannot be completely ruled out that broken glass can act as burning glass and that forest fires are triggered in this way, it is not likely. The majority of fires have other causes - and they are almost exclusively related to human activities: open flames, barbecuing, carelessly disposed of cigarette butts or even arson, to name just a few triggers.

Air only in the morning and evening

Airing in the morning, evening and at night is definitely advisable. But fresh air is also important during the day. Even if it's hot. A relief against the temperatures brings movement in the air, i.e. wind, for example through fans. Often it doesn't have to be the giant propeller, but a small device is quite enough to cool you down a bit.

In the summer we should only drink cold water

First of all, it is important to drink sufficient amounts. Non-alcoholic and unsweetened drinks - cold, lukewarm or whatever is tolerated. But please more than the often quoted two to two and a half liters per day. Three liters or more is advisable. This is a big problem, especially for older students, because in old age drinking enough usually takes more effort.

Heat is heat

Dry heat, such as in the desert or in a sauna without an infusion, is much easier than humid heat. Because the more water vapor is dissolved in the air, the more stressful and uncomfortable it is for us. In addition, humid air makes evaporation more difficult, which - driven by sweating - is important for cooling our body.

Tropical nights, summer and hot days - what is what?

There is repeated confusion with the definitions in the colorful summer world. It is a summer day when the temperature reaches the summer mark of 25 degrees. If the value rises to 30 degrees and more, then it is a hot day. In our latitudes, extreme heat is usually spoken of from 35 degrees. 20 degrees, on the other hand, is the lower limit for a tropical night. If it does not cool down below 20 degrees at night, then it is tropically warm.

Banish pillows, blankets and cushions from the apartment

What warms us is far from warming our four walls. Accordingly, it is quite humbug to ban pillows or blankets. That doesn't change the heat at all. In the meantime, of course, banning sunlight makes a lot of sense.

Heat is harmless - what are "silent storms"?

Storms are usually accompanied by bangs and bangs. After all, by definition they are extreme weather events, and in our perception they play in the haze of storms, thunderstorms or heavy rain. But heat waves are also extreme weather events - but silent or silent storms, which unfortunately can be accompanied by a high number of victims.

Above all, temperatures above 35 degrees significantly increase the mortality rate. In the extremely hot summer of 2003, for example, this meant that tens of thousands of people were assumed to have died directly or indirectly from the enormous heat throughout Europe.

(This article was first published on Tuesday, July 19, 2022.)