Frost Saints Days cooling since 1998 at meteoLCD

We all know since our earliest child days that in May there is a period of 5 days that often brings back severe cooling, before temperatures climb again into the summer numbers. The “Frost Saints” (or “Ice Saints”) are called “Eisheilige” in German, and are known as Mamertus, Pankratius, Servatius, Bonifatius and “die kalte Sophie” (from 11 to 15 May). The climatological cause is cold polar air streaming over a still cold nightly soil, which than often causes frost on this soil. This frost may destroy or damage young seedlings, so it always was something the peasants were afraid of.

Josef Kowatsch has an article in “Die Kalte Sonne” (English translation and comments at NoTrickszone) titled “Warum werden die Eisheiligen seit 25 Jahren immer kälter?“. Kowatsch shows that at 5 chosen German weather-stations the trend of the Frost Saints period is negative, i.e. these days are cooling. The station closest to meteoLCD is Bad Kreuznach, located 125km East of Diekirch. Here what Kowatsch has found for this station, located at practically the same altitude (184m asl versus 218m asl):

The cooling over the 25 year periods is – 0.14°C/year of -1.42 °/decade.

Now this pushed me to make the same analysis for meteoLCD, starting in 1998 (the “official” beginning of our data archive). Here is the result:

Same observation at Diekirch: since 1998 (23 years) the Ice Saints period is cooling; here the trend is -1.34 °C/decade, a quite impressive number. If one would foolishly extend this up to 2100, we would expect Ice Saints day more than 10°C cooler than today!

The plot shows that there are important variations w.r. to the linear trend line, which explains the poor R2 of 0.09. A Fourier analysis suggest 2 main underlying periods: about 2 and 10 years; the latter may be compared to the NAO (North Atlantic Oscillation) last period, which seems to be about 20 years… but this might be a coincidence.

The following graph from the excellent climate4you website shows that the heat content of the North-Atlantic changed markedly, with a cooling period following a warming:

The period of the oscillation in the green rectangle could be close to 20 years, the number discussed above for the NAO.

Conclusion

What remains to take home is that despite the ear-deafening shouts of the climate alarmists, the NGO’s, the politicians etc., there is some cooling going on: we are not in a situation of constant warming everywhere!

So it still might be prudent to not put all our eggs into the warming basket!