Is there a link with good weather?

THE summer days of this end of April 2025 understood their share ofaccidents On the main roads. The day of April 29 was memorable in the north, with collisions at the shovel, which occurred almost at the same time, at the end of the afternoon, on the A25, A1 and A16 motorways. The day before, on April 28, an accident between a bus and three vehicles paralyzed the RN 225, making the junction between Dunkirk and the A25, towards Lille. On April 30, it was this time the Phalempin area which was to be closed, due to an incident involving a heavy goods vehicle. The denominator common to these three days was the (very) good weather, which leads to wondering: Does the sun cause more road accidents ? The prefecture of the North brought some elements of responses.

Leisure trips increase when the weather is nice

The prefecture sends us back to the findings of the interministerial national observatory for road safety (ONISR). Based on the wide period of 2010-2019, they focus on road mortality, which “varies over the year”. The first quarter is “usually” the least deadly (21% of annual mortality over these 9 years analyzed), and the third deadliest quarter (28%). Of course, all this is to be put in perspective with the specific weather conditions, which are not the same over a given period from one year to the next.

In any case, the Onisr contrasts: ” Mortality increases when the weather is nice“. For a simple reason, it is that “the pleasant conditions induce an increase in travel, in particular for leisure trips« .

This is thus the case when the weekends preceded or followed by a public holiday (/bridge) are looming, and the prefecture of the North wishes to recall, on this subject, that “the police are mobilized on the occasion of prolonged weekends during which a strong road traffic is expected”.

Exceptional sunshine rate in March: more accidents on the North roads

Sunny days also promote more outings in so -called “vulnerable” movements of travel, such as bikes and motorcycles. The mortality of bikers, unfortunately, triple over the summer period, still according to the analysis of the Onisr. “Usually, the curve of biker mortality is strongly impacted by leisure trips, themselves linked to the summer: their average mortality in summer (June to August) is three times stronger than in winter (December to February). »»

Take the example of March 2025where the sunshine was more important in the north than in the south of France – Météo France highlights Calais, with +50% sunshine compared to normal. The Departmental Road Safety Observatory, which depends on the prefecture of the North, indicates that there was 98 bodily accidents on the roadsagainst 82 in March 2024 (which was however a very deadly month on French roads). This corresponds to 114 people injured, compared to 95 in March 2024.

The April 2025 results are not yet published, but it could confirm this upward trend.

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