By P Gosselin on 7. August 2021
From Die kalte Sonne
The German Weather Service (DWD) published its weather summary for July 2021:
July 2021 was significantly too wet, slightly too warm and lacked sunshine. […] In July, an average of about 110 liters per square meter (l/m²) fell nationwide and thus almost 40 percent more precipitation than the average of the reference period 1961 to 1990 (78 l/m²). Compared with the period 1991 to 2020, the increase was nearly 25 percent.”
Summer rains have returned
The DWD complained about summer drought several years in a row. Now the July rains are back. Climate is variable – which is weather. We look at July rains in a graph:
Shown are the individual values (July 2021: 110 mm) and the trend line since 1950, showing little change. Added to this is a 12-year low pass indicating internal variability. The thick line meanders back and forth without a trend in either direction. Using the new reference period (1991-2020), the DWD hides a period of lower precipitation before it, so now “too dry” appears in press releases more often. Not so this year.
No precipitation July trend change at all
There is apparently no trend toward less rain in Germany in July, even with global warming. Anyone drew conclusions based on the below-average values after 2017 is simply confusing weather with climate. We already had the observed similar deviation from the mean in the 1960s to 1980s. It’ll be interesting to see how the short-term media-born fairy tale of less precipitation in the summer in this country will be “corrected” in the coming years.
July 2021 normal using 1991 – 2020 mean
For temperature, July-2021 hit exactly the mean of the current period 1991 to 2020, which is good news. So the DWD also compares it with the old, discarded reference period to justify it was “a bit too warm” on its press release. DWD:
The July 2021 temperature average of 18.3 degrees Celsius (°C) was 1.4 degrees above the value of the internationally valid reference period 1961 to 1990 and at the same time exactly hit the average of the current and warmer period 1991 to 2020. Thus, the month was even cooler and little more summery than June.”
You just have to go back far enough, then you can make up the appropriate statement. Here is the graph:
You can see a warming trend: it is now about 1.5°C warmer in July than it was in the 70s. There is a lot of variability here as well. The unchallenged leader is still the year 2006. So the decadal filtered average (bold) remains at about 18.6°C since 2004, currently we saw 18.3°C. Consequence of the warming thus: Warming, as not to be expected differently.
via Watts Up With That?
August 8, 2021