21 March 2018 /
| 0 to 5 degrees | Bloody freezing | The preferred temperature for extreme winter swimmers. Causes pain and takes your breath away. Except for the very experienced, and only under strict supervision, swims should be limited to a few minutes. Enjoy the buzz when you get out. |
| 5 to 10 degrees | Effing cold | Typical lake and river temperature in early spring. Still painfully cold and not recommended for anything other than very short swims (5 to 10 minutes) unless you are very experienced. |
| 10 to 15 degrees | Nippy or ‘not as warm as we like it’ | Open water starts reaching these temperatures in late spring around much of the UK. At the lower ends, it will still feel extremely cold initially but longer swims are now possible. Experienced swimmers can manage several hours or more as the water approaches the mid teens but hypothermia is still a big risk. |
| 15 to 20 degrees | Alright (once you get used to it) | The English Channel in summer. If you’ve only ever swum in a pool, this will feel cold but with a bit of experience and practice most people find this range comfortable, at least initially. |
| 20 to 25 degrees | Balmy | Rarely reached in the sea around the UK, but sometimes in inland lakes. If you’re a habitual wetsuit wearer then seriously consider removing it at these temperatures to avoid overheating. Very pleasant. |
| 25 to 30 degrees | Stifling | Like a swimming pool. Some open water swimmers find these temperatures too high for serious swimming. Make sure you have plenty to drink. Don’t wear a wetsuit. |
| 30 degrees plus | Hot | Avoid strenuous swimming as there is a definite risk of heat stroke. |
Note, swimmers have widely differing opinions about comfortable water temperatures and people’s bodies respond differently. Learn to trust your own experience and feelings.
By Simon Griffiths
Jumping in is likely to impair breathing in the uninitiated, as breath comes in big jolting gasps and it feels like someone has clamped on an ice neck brace. Water has bite, skin smarts and burns. This is winter swimming. Limbs soon become weak – 25 metres can be an achievement – and only takes a minute or two at the lower end of temperatures before skin becomes a lurid purple-orange-red (for those with lighter skin) when you exit.
That said, the joy of swimming without a wetsuit at this end of the temperature spectrum is the cold water high: the pure exhilaration and rush of endorphins that you get from getting in. Winter swimmers frequently become addicted to it, and it is sufficiently powerful that a 1-2 minute swim can leave you feeling good all day. Anecdotally winter swimming clubs like Serpentine Swimming Club and Tooting Bec Swimming Clubs report increased immunity and fewer colds.
6-11 DEGREES: Freezing
Much like baltic, but not quite so painful, or breathtaking.
12-16 DEGREES: Fresh
At this temperature triathlons start operating. In a wetsuit you may find you can swim comfortably for a while, outside of one the water is fresh, doable for the brave, and not a problem for hardened open water lovers.
17-20 DEGREES: Summer swimming
Lakes and more mature rivers reach this temperature over summer, during hot spells. Still fresh on entry, but comfortable picnic lazy-hazy summer swimming.
21 DEGREES PLUS: Warm
You’d think that’d be a good thing, but on the rare occasions that river pools and shallow lakes reach these temperatures during hot spells, there is the odd sense that there’s something missing…. the exhilarated feeling when you get out, that cold water ‘tang’. On the plus side, some of you will be able to spend hours swimming without a wetsuit.
30 DEGREES: Pool temperature
Arguably unpleasant. Plus, as Rob Fryer comments, ‘the sun is not invited’.
The right water temperature for swimming can make your pool session safer and more comfortable.
Image Credit: Alvaro Medina Jurado/Moment/GettyImages
Don't ask members of the Coney Island Polar Bear Club how warm it has to be to swim. These winter swimmers plunge into the Atlantic Ocean every Sunday from November until April and revel in the chill.
Ultimately, swimming temperature is a matter of preference — some people can tolerate much colder temperatures than others. People even acclimatize themselves to swim in the Arctic for short distances.
Generally, water cooler than 60 degrees Fahrenheit poses danger to swimmers who go for longer than two hours.
Good Water Temperature for Swimming
Swimming expends lots of energy, and if the water temperature isn't within a certain range, it won't allow your body to function properly, possibly leading to some serious problems.
Your age, weight and what type of swimming you're planning on doing — such as leisurely laps or vigorous racing — determine the temperature considered safe for you.
- For lap swimming or racing, the temperature should rage from 78 to 82 degrees Fahrenheit.
- For children and older adults, higher temperatures ranging from 82 to 86 degrees Fahrenheit are recommended.
- Since babies are smaller, they have a hard time regulating their body temperatures, which means the water should be 84 to 86 degrees Fahrenheit.
- For people who have obesity, the water should be between 80 and 86 degrees Fahrenheit.
- For those who are pregnant, the water should be between 78 and 84 degrees Fahrenheit.
Of course, this guide to safe water temperature for swimming assumes you're healthy; if you have any health conditions, check with your doctor to determine the right temperatures for you (or if you should be swimming at all).
Cold water zaps your body heat 25 times quicker than cold air. Add to that the physically exhausting nature of swimming, and you're losing body heat at a rapid pace. What pool temperature is too cold? Extremely cold water — 50 degrees or below — can lead to cold shock.
This occurs when the body is overwhelmed by extreme cold, and it can lead to a heart attack or unconsciousness, which can lead to drowning. Your body responds to a sudden plunge into cold water by making you involuntarily gasp, and if you're under water this can cause you to drown before you get to the surface.
Another concern is hypothermia. While it takes longer than cold shock to set in, it can be just as serious. Exposure to cold water for long periods of time lower your core body temperature. After two hours in 60-degree Fahrenheit water, your risk of unconsciousness and death by drowning increases to 50 percent.
The lower your body temperature gets, the less your body can function. Once your core temperature reaches 93 degrees, you'll be unable to use your arms and legs, and your mental function begins to deteriorate. At 80 degrees, you can become unconscious and drown.
You can tolerate cold-water swimming for more time when wearing a wet suit, neoprene cap, gloves and booties. For example, USA Triathlon permits competitors to wear wet suits in water colder than 78 degrees Fahrenheit.
On the flip side of hypothermia is hyperthermia. This happens when the water is too hot. Swimming for long periods of time in high temperatures doesn't allow the body to properly cool itself. When this occurs, side effects can include nausea, light headedness, dehydration or heat stroke.
So what water temperature is too hot for swimming? If you're planning on high-intensity swimming, cooler water under 82 degrees is needed.
US Masters Swim suggests specific temperatures for pool water. Younger children and older adults generally need warmer temperatures ranging from 84 to 94 degrees Fahrenheit, while a comfortable pool temperature for adults is 85 to 89 degrees Fahrenheit. If you're swimming for fitness, cooler temperatures of 78 to 84 degrees Fahrenheit are recommended.
How to Stay Safe While Swimming
While you probably won't be taking a thermometer with you on your next trip to the pool, there are ways to stay safe while swimming. Enter the water slowly to test it instead of diving in. If you feel nauseous or lightheaded, take a break to cool off. And bring plenty of drinking water.
Off-season water temperatures can be dangerous, and even if you're on a boat and not planning on getting into the water, accidents can occur. Bring warm clothing with you to decrease the effects of cold shock or hypothermia in case of such accidental exposure.
Don't forget: Just because it's warm outside, doesn't mean the water is warm too.
Related Reading