Media Hype Exposed: Summer 2025 In Germany Was Neither Too Hot Nor Too Dry

By Klimanachrichten here^[1]

We have already reported on the meteorological August^[2] and its preceding months here^[3] and here^[4].

Now, we present here the average figures for the entire summer according to the official DWD data^[5], which always appear with a slight delay.

The pure facts for the last 101 years, Germany T2m summer temperature and precipitation in millimeters:

The 18.3°C reached is already warm: only nine years previously had higher values been recorded, only one of which (1947 with 18.5°C) was before 1980. The increase since then is obvious.

However, 2025 was still a long way from the record (2003, 1.4°C warmer). Last summer did not “feel” too warm. The reason for this is probably the 30-year smoothing (bold): until around 1980, there were only slight ups and downs; in the 1930s to mid-1950s, it was slightly warmer than in the 1960s and 1970s. The most likely reason for this is a natural fluctuation in the AMO, which influences local summer temperatures, as has been known for some time. From 1975 to 1981, it was often significantly “too cool” for this, with the AMO switching to “negative.” “When will it be a real summer again?” wrote Rudi Carrell in 1975, and he was right at the time. Last year, the average temperature was almost 2°C warmer, and yet the song experienced a “quotation renaissance.” Here, too, smoothing helps in the search for the reason: “collective memory” changes with experience, and hardly anyone can remember the weather more than 30 years ago, even if they could. And 2025 was just below that! The fact that this smoothed average is now 2.4°C higher than at the time of the evergreen is beyond individual experience. The data does not lie, and it was warmer in the end, but rather at the low end of the expected range.

When it comes to precipitation, we can be more concise: 75 of the previous years were wetter, while 25 were drier. Overall, rainfall was “perfectly normal” at around 219 mm. The harvest was quite good^[6], contrary to fears in the spring, some of which were expressed in quite dramatic terms: “Germany is drying up.” Some people were probably premature in calling for subsidies for agriculture. Some still need to learn^[7] that water is part of a cycle and is not “consumed.” What evaporates will sooner or later fall back to earth as precipitation elsewhere.

There is also no real long-term trend in precipitation; the 30-year smoothed curve is still trending downward at the end due to the really low values of 2018 (129 mm) and 2022 (143 mm).

Heat in Berlin or “Summer in the City”

The million-selling hit by Lovin’ Spoonful from 1966 has probably also made it into the “collective memory.” We had already looked at a value for “physiological heat” last year^[8] (the result at that time: no hellish summer in 2024, it was still 2/10 °C warmer on average than this one) and most recently at the beginning of July^[9] this year.

Once again, a brief explanation of this. How “hot” it is is not only determined by the maximum temperature of the day. We actively evaporate to cool ourselves, and this works much better in less humid air than in more humid air. Eckart v. Hirschhausen certainly learned this during his medical studies, as “human physiology” is a compulsory subject. So why he ignores the active cooling of humans (“at just over 42°C OUTSIDE, the brain denatures^[10]”) remains his secret.

A very efficient measure of humidity is the dew point. This is the temperature at which dew forms. If you cool a container of water (or beer) with ice outdoors, at some point the container will become fogged up. If there is a lot of moisture in the air, this will happen at a higher temperature than if the air is dry. The combination with the maximum temperatures is now done by simply adding the values day by day. This is added up and, in order to distinguish real heat from just warm days, there is a limit: if the sum exceeds 44°C, the difference between this threshold and the value reached is added up. Up to 44°C, therefore, zero.

A comparison of the years then produces this diagram:

It quickly becomes clear that in Berlin and the surrounding area (the situation will be different in southwestern Germany, but long-term heat observations can only be made “locally,” and Berlin is home to the largest population of any single city), the summer was only slightly above average in terms of heat compared to the years 1981-2010. The only really serious heatwave lasted only from August 12 to August 15 of this year. But then it was intense, with a maximum temperature of up to 35°C and a dew point of 18°C on August 15.

However, it did not last as long as, for example, in 2015 from August 2 to 15, and the “long-term effects of the heat” could hardly unfold. What did the residents experience in 2006 and 2019! In contrast, 2025 was literally “undercooled.” And that’s exactly how it felt throughout July until the “mini heat wave” in mid-August. That at least brought the final value up to the 1981-2010 average.

So, by definition, summer 2025 has come to an end. All in all, in the context of the last 30 years, it was by no means too warm or too dry. Will some media outlets learn from this when they produce “forecasts” with bold headlines (=clickbait) again, used for apocalyptic statements? The next winter is not far off, and the countdown to crazy weather stuff is already underway.