Why are we wrong about what a “normal” summer should be like?

After the historic heat of 2022, marked by four waves HeatHeat Including very early heat wave DryDry At the record range, and the big fire, 2023 doesn’t quite take the same turn. The current summer consists of very warm periods (including a heat wave in the southeast in July) and cool periods. Surface dryness, which was very severe at the end of spring, almost completely disappeared after spring thunderthunder of the month of June. conditions weather reportweather report The current summer is actually much less unusual than the very hot and very dry summer of 2022. With global warming, our image of summer has completely changed: for many French people, summer necessarily equates to hot, perpetually sunny and warm days. Dry period, from June to September. The past years have made us accustomed to the summer period sometimes lasting from March to October. However, 6 months of hot and dry weather is not considered the norm in France, nor is 3 consecutive months of hot and dry weather. The global rise in temperatures has made us completely forget what a “normal” summer used to be like in France.

The summer season in France obviously corresponds to a generally warmer and brighter period than the rest of the year, but there are natural variations in these three months (June, July, August).

June, a few years ago it is still possible to get frost in the morning

In June, good weather is never guaranteed in France: it rains an average of 8 days a month (a quarter of the month) in Paris, 7 to 10 days in the southwest and the Alps, and 9 to 10 days in the Grand. Estimate (i.e. one third of the month). If the average reaches 24°C in Paris and 26°C in Marseille, there can be a big difference. In the 1990s, morning frosts were recorded in the plains of the Ardennes and Normandy, which we are no longer used to, or are much smaller.

10 rainy days on average in July

In July, the classic weather is hot, sometimes sweltering and stormy. It rains on an average for 9 to 10 days in the far north of the country and 2 to 5 days in the southeast. Throughout France, July has an average of 10 rainy days, or a third of the month due to heavy rain storms. In the past, despite possible heat waves, morning frosts were sometimes strong in some areas: until the 1950s, mornings north of the Seine, such as in Picardy, or even in the north-east freezing was possible, which is clearly not the case now. , The average temperature in Paris is 25°C, only 21°C in Brest and 29°C in Ajaccio. So it should be remembered that temperatures of 30°C in the north and 40°C in the south are well above average. The warming is no surprise, but the recurrence of extreme temperatures testifies to what meteorologists call an anomaly.

August is a very variable month in terms of temperature

In August, temperatures are roughly equal to July, but readings from previous years show that the weather is more variable: the month can be extremely unusually warm (as in 1997, 2003, and 2022), but Also unusually fresh (as in 1985, 2002, 2008 and 2014). It rains an average of 7 days in Paris or 10 days in the Grand Est region: it is not unusual for a full week of rain during the month of August, even if these rainfall figures are also associated with stormy days throughout the month. ,

Finally, summer isn’t basically a uniform period of full SoleilSoleil Temperatures above 30°C are everywhere in France DurationDuration School Holidays: This erroneous approach is largely influenced by the recent (and much longer) summers affected by global warming.

article of carin durandcarin durandwrote on August 2, 2023

After an unusually warm month of July, August begins with unusually low temperatures. With global warming, how can it be so cold at a time when temperatures are usually the highest of the year?

Every month since February 2022 has ended with a temperature surplus. With +0.8°C compared to the average, July 2023 was no exception to the new norm. But this early August marks a paradigm shift that could be worrying: late July–early August is on average the warmest period of the year.

Jet stream and depression in early autumn

Heavy rain, northwesterly storms bordering on hurricane force, and above all, a generalized chill will dampen the spirits of vacationers for more than a week. This Thursday 3 August, Friday 4 August and Saturday 5 August there will be a very noticeable drop in temperatures everywhere in France, including the south-east: locally, it is not impossible that a month of August could be a monthly cold record. drawing near, especially in the morning. In the northern part of the country, values ​​will be in line with what can be expected in October. And this change in autumn weather could be quite durable, at least until August 10.

After the dome of heat in July, it appears that the month of August begins with a “dome of freshness”: the term does not exist in the season, but corresponds to the feelings of some French people. Temperatures will actually be -4 to -6°C below average seasonseason, in question, a real dip of jet stream South side: It is a high altitude stream, which separatesAirAir The cooler to warmer air will undergo a rapid oscillation between Friday and Saturday. A loop will go south leaving France and Spain masse d’airmasse d’air It is getting cold all over our country too. There will be a big shock in Lyon: 10°C less in 48 hours!

Despite occasional severe storms and more gloomy weather in the northwest, the weather in July was ultimately fairly classic: conditions were generally high-pressure, with a 10-day heat wave in the southeast. But, starting in early August, the weather is classic for a while.Winter seasonWinter season, It is marked by a series of active and hollow depressions, resulting in much of the country’s rainfall.

Natural variability continues despite warming

However, in the cool and humid conditions of mid-summer this type of wilting is not so uncommon. This situation occurs regularly, as it did in July 2021. Despite some global warming, the weather is still (and fortunately) subject to natural variations. The increase in temperature associated with climate change occurs over a longer period of time, even though there are sometimes more intense years with actual climate change. So global warming doesn’t prevent cool and wet periods in summer, and probably doesn’t prevent “totally rotten” summers either.

let’s remember that Climate consistent with average for at least 30 years, and that the weather is consistent over a period of a few days to a few weeks, and up to three months for seasonal weather forecasts. In recent years global warming has accustomed us to very hot, very dry and very long summers, to such an extent that we have forgotten that along with summer in France there can be cold and gloomy periods.