This week is set to be hottest of year in France: How hot and where?

Expect the nights to be warm too. We share tips for the home, garden, car, pets and health

A man holding a thermometer showing 40C against an urban background
With temperatures set to climb, there are tips you can follow to stay cooler and more comfortable
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Temperatures of 35C and above are predicted in several areas of France this week - and again next week - as hot weather spreads across the country from the east.

We give tips to stay cool and protect your home, car, garden, and pets from the hottest heatwave yet this year.

Forecaster La Chaîne Météo has said that “the week is looking like the hottest of this summer”, with forecasts of 35-40C. A mass of hot air rising from the Sahara will also mean that night time temperatures will remain high, at between 18-23C.

How hot will it be, and where?

Forecasts show that the Rhône-Alpes region will be most affected until Wednesday, August 16, with temperatures of around 35C during the day, and no less than 16-20C overnight in Lyon, Saint-Étienne, Grenoble, Ambérieu, Chambéry, and Annecy.

At the time of writing, the area is still on orange alert (the second-most severe) for a heatwave, comprising the departments of Rhône, Ain, Isère, Haute-Savoie, and Savoie.

From Thursday, August 17, the heat will spread to the Loire, with temperatures of 30-35C across most of the region.

From Friday, August 18, the heatwave is expected to have spread to two-thirds of the country, and temperatures will hit 37C in Rhône-Alpes, and up to 30C in Hauts-de-France. In the northwest, temperatures will still reach 25 to 29C.

Around 80% of the country will hit maximums of 30C, and overnight conditions will remain at 20-22C, especially in large cities in the south.

Over the weekend (August 19 and 20), an anticyclone from the north will cause temperatures to drop in the northern regions, with storms expected north of the Loire. Temperatures will decrease north of Bordeaux to Lyon but conditions will remain hot in Occitanie, Provence, and the Rhône-Alpes. The mercury could even hit 40C in Provence.

The heatwave is set to continue into next week, including in northern regions. Early forecasts suggest that the heat will continue to rise towards Germany and Benelux, with temperatures of above 30C across most of France. Paris could even see 35C, and areas of the southwest could hit 40C.

The conditions may begin to abate in the middle of next week, early predictions show.

Why will it be so hot?

Loïs Pourchet, forecaster at Météo-France, told FranceInfo: “We've been seeing a southwesterly flow for several days now, with high pressure over the Mediterranean and a low-pressure system over the Atlantic. This is bringing warm air to the centre-east of the country.”

The low-pressure system effectively works like a heat pump, and will eventually cause storms as the heat intensifies.

Mr Pourchet advised people to avoid sporting activities and to hydrate well.

What is an official ‘canicule’ in France?

The official definition of a heatwave, or canicule, in France is applied when high temperatures persist for three days and three nights consecutively. However, the threshold for a ‘high temperature’ differs by region.

The threshold is determined by a range of factors for the region, based on data from the past 30 years, including the average temperature for the season, maximums and minimums, and mortality rates.

The different thresholds take into account the fact that some parts of France are more accustomed to higher temperatures than others.

For example, Météo France states that:

  • An official heatwave would be declared in Deux-Sèvres when temperatures are a minimum of 35C during the day and 20C at night for three consecutive days and nights.
  • In Haute-Loire, however, the threshold is 32C during the day and 18C at night.
  • In Paris, it is 31C during the day and 21C at night.
  • In contrast, in Marseille, where temperatures are usually higher, it must be 35C or more during the day and at least 24C at night for an official canicule to be declared.

How to keep your house cool

  • Close windows and shutters during the day to keep the peak of the heat out.
  • Turn off electrical appliances during the day, as they create extra heat indoors.
  • Place plants on your balcony, terrace or next to windows. They can absorb water from the soil and then spread it into the atmosphere, keeping the air cooler.
  • Mist your plants and room to keep the air cool.
  • Air out rooms in the early morning and late evening to let the very hot air escape.
  • Place a fan next to doors or windows and hang damp sheets or towels at the windows to drop temperatures inside the room. Place iced bottles of water in front of fans.
  • Keep windows open at night if possible to allow cooler air to circulate as you sleep.
  • Place your bedding in a bag and place in the freezer for a few minutes, before getting into bed.
  • Use 100% cotton sheets.
  • Put a tightly-sealed bottle of cold water in your bed.

How to protect… your garden

  • Water plants in the early morning and late evening so they have more chance to absorb the water, to stay protected during the heat of the day. Watering during the day’s peak will simply mean that most of the water evaporates.
  • Do not ‘drown’ your plants with excess water. Not only is this not good for their health, but it can also stop them from putting down deep roots to absorb enough water. It may appear counterintuitive, but giving them less water - perhaps every few days rather than every day - can help their long-term health.
  • If the soil still feels damp, or the plant’s leaves have brown or yellow patches, they may be overwatered. Leave them a day or so to dry out before watering again.
  • If your plants are suffering in the heat, you can cut down excess growth from larger plants. This means that they will need less water in the short term and will grow new shoots in the long term when the weather cools.
  • In the long term, choose plants that are well-adapted to drier conditions. If your garden is often dry during the summer, choose Mediterranean plants that can adapt well to hotter, drier weather.
  • Do not use very cold water to water plants as it can ‘stress’ them. Instead, use room-temperature water, even during a heatwave. You could fill a watering can and let the water heat up during the day, and then use this to water your garden in the evening.
  • You may also wish to install a drop-by-drop watering system in the long-term too, as this can be a more effective way of keeping plants watered consistently at the root, without wasting water.

How to protect… your car

Vehicles can also suffer in the heat, especially if you drive them at peak times during the day or leave them parked in full sun.

Motor components can become damaged in the heat, especially if you are, for example, sitting in a traffic jam in the heat with your air conditioning on full.

Your breakdown plan may cover issues related to heat, either through its mechanical breakdown cover, windscreen cover, or other repairs - but this does, of course, depend on your policy.

During extreme conditions, it is advisable to:

  • Keep an eye on warning lights and motor temperature indicators. The best temperature for a motor is around 80-100C. Any hotter, and it is at risk of overheating. White, opaque smoke from an exhaust may also indicate a problem.
  • If your engine is overheating, turn off the air conditioning and cut the motor where possible, while still leaving the fans on. Park in the shade, and let your car cool down. This may take 30-45 minutes. Changing the oil, when the engine is cool, may also help.
  • Charge your battery before a long journey, if you fear it may be low. Extreme temperatures can damage its functioning, and it is called upon more during heatwaves for air conditioning.
  • Check your coolant and make sure it is at recommended levels for your vehicle.
  • Check tyre pressure. Excess heat can damage tyres and even cause them to burst. Check your tyres’ wear and replace them if the treads are low.
  • Turn down your air conditioning gradually. Open your windows at first, to let the car cool down slowly. This can also protect your windscreen. Then, close the windows and set the aircon at 5-7C lower than the outdoor temperature.
  • When parked, protect your car from excess heat. Try to park in the shade, and cover your windscreen and other windows with protective covers where possible.

How to protect…your pet

Your four-legged friends can also suffer in the heat. Advice includes:

  • Never leave your pet in the car. Even with a window down in the shade, the temperature inside a car can quickly reach 60C in a few minutes.
  • If you see an animal suffering in a car, try to find the owner. If you are unable to do so, you can call the police or gendarmerie and alert them to an animal in distress. They have the authority to break into a vehicle to save an animal.

Avoid walking your pet during the heat of the day. They can easily overheat, and burn their paws on hot ground. Instead:

  • Take them out in the early morning or in the evenings after 21:00.
  • Take water with you and let them drink as much as they need.
  • Try special ‘shoes’ on your dog if you fear they could burn their paws on hot tarmac.

If your pet - whether a dog, cat, rabbit, or otherwise - appears to be suffering in the heat, take fast action. Animals can suffer from heatstroke just as quickly, if not more so, than humans. They might appear lethargic, or pant more than normal.

  • Take them somewhere cool.
  • Give them cool (but not iced) water.
  • Wrap them in a damp sheet to bring their temperature down.
  • Consult your vet as soon as possible.

How to help others

Elderly people, pregnant women, the very young, and the most vulnerable are at the highest risk of suffering most during very hot weather.

Be sure to check on vulnerable people in your area, and stay alert to people when you are out and about (such as shopping, doing errands, or taking public transport).

You are also advised to avoid going out during midday and 16:00 where possible, and to stay hydrated and drink at least 1.5 litres of water per day, if not more.

It is best to drink little and often, rather than drinking a lot in one go. This can be dangerous in itself. Similarly, drink cool (but not iced water), and take cool but not too-cold showers, as the very cold water can actually cause you to feel hotter in the longer-term (as your body seeks to warm up).

If someone near you feels unwell or faints due to the heat, follow this first aid advice:

  • Lie the person down, and/or try to move them to a shaded or air-conditioned area.
  • Place a damp towel on their face.
  • If they can, ask them to sit up and drink cool (but not iced) water.
  • Ask if they have any medical conditions that could be affecting them.
  • If in doubt - especially if the person is elderly, very young, or especially fragile - you can call the SAMU on 15 to make sure they are checked and well cared for.
  • If the person ever falls unconscious, even briefly, put them in the recovery position (lying on their left side, their top knee bent, and their top arm bent and reaching next to their face) and call 15.

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