The French sleep pretty well, but not in the same way all year round. Withings data shows that some months offer a real recovery bonus while others sabotage it. The difference between winter nights and summer evenings remains striking.
The study reveals a very clear sleep calendar, with one month clearly more favorable than another for sleeping well. Understanding what is special about it allows you to adjust your room and routines, to bring the rest of the year closer to this level of recovery.
Sleep well: what the Withings study reveals about the months of the year
According to Withings, France has an average Sleep Score of 74/100 and ranks second in the world, behind Finland. The average duration of sleep reaches 7 hours 20 minutes per night in 2025, compared to 7 hours 30 minutes in 2024, or ten minutes less over a year.
The analysis of sensors such as Sleep Analyzer or ScanWatch reveals above all a strong seasonality. The month of February appears to be the most conducive to recovery, January 5 offers the best night of the year with a score of 82.24, while July 1 falls to 65.66, almost 17 points difference.
Why February is the most favorable month for better recovery
In the middle of winter, the outside temperature facilitates a drop in the body’s core temperature, which is essential for falling asleep. A room set at around 18 to 19°C helps this thermoregulation, while above 20 or 21°C the body does not evacuate heat well and deep sleep becomes fragile.
Winter darkness also promotes the secretion of melatonin. In February, the evenings remain long and natural light diminishes early, which limits light pollution. From March onwards, we sometimes keep our heating reflexes strong as the days get longer, a duo which is already starting to degrade recovery.
July, heat and light: how to limit sleep loss
If July 1st shows the worst score of the year, the nighttime heat largely contributes to it. Hot air prevents the body from cooling and maintains continuous agitation. Keeping the bedroom cool and airy morning and evening, with breathable cotton or linen bedding, helps you better endure these nights.
The late light and the noise complete this summer cocktail. A simple alarm or charger LED, a sound level above 30 decibels, is enough to reduce deep sleep. When the bedroom becomes cool, dark and quiet again, the duration of deep sleep can increase by more than 20% depending on the season.
What is the best month to sleep well?
The Withings study shows that the most favorable month for recovery is February, thanks to cooler and darker nights.
Why do we sleep less well in July?
Nighttime heat, late light and a more intense social life disrupt thermoregulation and reduce deep sleep.
What is the ideal temperature for sleeping well?
A room around 18 to 19°C is ideal; above 20 or 21°C, the body dissipates heat less well.
