With this weekend’s forecast pointing to a return of summer heat and heatwave conditions across much of the UK, many of us will no doubt be looking for ways to cool off.
As temperatures rise, many of us are drawn to the water, whether it’s a trip to the beach, a swim in a lake, or a paddle in a river. But while the sun may be shining, the water can still pose serious risks. One of the most dangerous is cold water shock.
Cold water shock is a sudden and involuntary response that occurs when the body is unexpectedly immersed in water below 15°C. Even on a hot day, the sea, rivers, and lakes in the UK can remain cold enough to trigger this reaction. It’s a physiological response that can affect anyone, regardless of age, fitness, or swimming ability.
If you’re heading to the beach over the next few days, be aware that the water around the UK can still be cold.
— Met Office (@metoffice) July 9, 2025
Follow the advice from our friends @RNLI to avoid cold water shock. #RespectTheWater #FloatToLive @HMCoastguard pic.twitter.com/ElvmZ51otV
What happens during cold water shock?
When you first enter cold water, your body reacts instantly. The sudden cooling of the skin causes an involuntary gasp, which can lead to inhaling water. Your breathing rate increases rapidly, and your heart rate spikes. This can cause panic, disorientation, and even hyperventilation, making it difficult or impossible to swim.
Even strong swimmers can be overwhelmed by cold water shock. The initial effects typically last for around 90 seconds, during which time it’s crucial to stay calm and avoid unnecessary movement.
What to do if you fall into cold water
The Met Office, RNLI, and RLSS UK, recommend the follwowing advice. If you unexpectedly find yourself in cold water, the most important thing is not to panic. Fight the instinct to swim hard or thrash about. Instead, follow these steps:
- Lean back and try to float, keeping your head above water.
- Extend your arms and legs to help you stay afloat.
- Control your breathing, this is key to surviving the initial shock.
- Once you’ve calmed your breathing, call for help or look for something to hold onto.
- If possible, swim to safety only once you’ve recovered from the initial effects.
This simple technique, known as “Float to Live”, can save your life.
READ MORE: Learn about the Water Safety Code
Planning ahead for water activities
If you’re planning to enter the water for swimming, paddleboarding, or any other activity, preparation is essential. Always check the weather and water conditions before heading out. The Met Office provides up-to-date forecasts that can help you assess whether it’s safe to go.
Wearing the right gear is also important. A wetsuit or drysuit can help insulate your body and reduce the risk of cold-water shock. A personal flotation device (PFD) is vital for many water-based activities and can keep you afloat if you get into trouble.
Know your limits
It’s easy to underestimate the power of open water. Currents can be stronger than they appear, and cold water can sap your energy quickly. Never push yourself to swim further than you’re comfortable with, and always plan your entry and exit points before getting in.
Learn to recognise the signs that you’re getting too cold. Shivering, weakness, disorientation, shortness of breath, or taking in water are all signs that it’s time to get out. Once out of the water, warm up immediately with dry clothes and a hot drink. A brisk walk can also help raise your body temperature.
READ MORE: 10 beach safety tips
Stay together, stay close
Whether you’re heading to the beach, a river, or a lake, it’s always safer to go with others. Let someone know where you’re going and when you expect to return. Choose lifeguarded venues whenever possible and keep an eye on each other while in the water.
If you see someone else in trouble, don’t enter the water yourself. Instead, call 999 and ask for the appropriate emergency service, HM Coastguard if you’re at the coast. Look for public rescue equipment like throwlines or find something that floats to help them while you wait for help to arrive.
Be prepared and stay informed
To enjoy open water safely, it’s important to be well-equipped and informed. Here are some key tips:
- Swim at a lifeguarded beach: The RNLI has around 1,500 RNLI lifeguards (including volunteers) on over 240 beaches around the UK.
- Check the weather: Use the Met Office forecast to assess wind, rain, and temperature conditions as well as UV levels, even if it doesn’t look sunny.
- Wear appropriate gear: A wetsuit and tow float can provide warmth, buoyancy, and visibility.
- Wear brightly coloured swimwear: This helps others see you in the water.
- Practice floating: Teach children and adults alike how to float on their backs and stay calm in the water.
- Avoid inflatables at the coast: These can be swept out to sea quickly by wind or currents.
READ MORE: Tips for keeping cool in hot weather
Learn the water safety code
The Royal Life Saving Society UK (RLSS UK) promotes the Water Safety Code, which includes four key messages:
- Stop and think - spot the dangers.
- Stay together - always go with someone else.
- Float - if you fall in, float until you can control your breathing.
- Call 999 - in an emergency, get help immediately.
You can find more resources, including videos and printable guides, on the RLSS UK and RNLI websites.
Cold water shock is a serious risk, but with the right knowledge and preparation, it can be managed. Whether you’re a seasoned swimmer or just looking to cool off on a hot day, understanding how your body reacts to cold water, and knowing what to do, can make all the difference.
Samantha Hughes, from the RNLI’s Water Safety team, said: "With the hot weather forecast for this weekend, please do visit a lifeguarded beach and to swim between the red and yellow flags or choose a supervised swim location. Although the air temperature is rising, the water temperatures remains low enough to cause cold water shock. Enter the water slowly, take time to acclimatise and try to relax. If you get into trouble in the water, Float to Live. Tilt your head back with ears submerged and try to relax and control your breathing. Use your hands to help you stay afloat and then call for help or swim to safety if you can. If you see anyone in trouble in the water call 999."
Keep up to date with weather warnings, and you can find the latest forecast on our website, on YouTube, by following us on X and Facebook, as well as on our mobile app which is available for iPhone from the App store and for Android from the Google Play store.