Evidence of global warming? Temperature readings, carefully scrutinized by meteorologists. The conclusion is clear. Lyon today has the same climate as Montélimar, in the Drôme, thirty years ago. And Montélimar, the same as that of Nîmes, city of Gard. As for Strasbourg or Dijon, they have that of… Lyon in the 1990s.
From 1991 to 2020, the mercury rose by an average of 0.6°C in the capital of Gaul. Few, some will answer. However, the difference is palpable on the ground. Rainfall decreased by 10% and sunshine increased by 2%. Compared to the period 1981-2010, Lyon now records 7 days more per year during which temperatures exceed 30°C. “There are also 10 days less frost per year and 9 additional days when the wind blows at more than 50 km/h”, develops Romain Weber, founder of the site. Lyon weather.
From continental to Mediterranean climate
“The Mediterranean climate has returned to Lyon, which benefited from a continental climate, sums up the young man. Before, we had hot summers and very cold winters. Today, there is no longer a cold winter. The record of -24.6°C, observed on December 22, 1938, is not about to be beaten. “From now on, the mercury had a hard time dropping below -5 degrees, but above all the winter has been considerably shorter. We are on a one-month season, ”says Romain Weber.
Another notable change: the spring season is also “shorter and shorter”. “If you look, we generally have an autumn that stretches from the end of October to the beginning of April, even if we can have a cold month in the middle. There are no longer marked seasons as before,” notes the meteorologist.
Lyon, second most impacted city in France in 2040
Periods of drought which intensify over the years, the recurrence of heat waves and their duration are other indicators of global warming. For example, in the 2000s, there were 11.5 days of intense heat in Lyon, compared to 3.6 in the 20th century. If the trend is general, the phenomenon is particularly convincing in the capital of Gaul. According to a report by The European Data Journalism Networkpublished in 2018, Lyon is the largest city in France affected by global warming in 117 years.
There are two reasons for this: “a cruel lack of green spaces” and its geographical position at the exit of the Rhône valley, suggests Romain Weber for whom the situation should intensify in the coming years. According Le Figaro, who compiled the projections of climatologists concerning after 2040, Lyon will be the second French city most impacted by the future rise in temperatures (14.8 days, 11.9 nights), just behind Annecy and ahead of Saint-Etienne, Avignon and Valence. According to the most pessimistic forecasts, it should even make Lyon the climate of Algiers in 2100…