Best Practices in Open Water Winter Swimming
Everything you need to know before you 'swim down the thermometer.'
Even as water temperatures drop, the lure of open water remains. It’s the exhilarating rush and nervous system reset, especially during the stressful holiday season or when you’re looking to clear away the winter blues.
Safety is paramount; be diligent about yourself and those you swim with.
Know Your Limits
As you “swim down the thermometer,” your time in the water may be less, but your enjoyment doesn’t need to be. Tracking your cold water tolerance and your typical swim can help you make better decisions.
If you plan to swim through the winter, start logging your swim duration and the water temperature. Don’t overthink it. Jotting it down on the calendar or making a note in your phone is fine. Some swimmers choose to increase their time in small increments (e.g., 5 minutes) when they swim a few times a week and want to swim longer. As the water temperature decreases or you aren’t swimming as frequently, dial back your time in the water. If you’re swimming infrequently or miss a few swims, many swimmers scale back their time to let their body adjust before trying to stay in longer.
Remember, we’re talking about time in the open water, not distance.
Winter Water Temperatures and Weather
Beyond falling air and water temperatures, winter changes things up. If you swim in a place like the San Francisco Bay, winter can bring shifting wind patterns and unfamiliar wave directions along with high wind storms and debris in the water. If the wind is blowing and conditions look beyond your ability, take a pass and swim another day. No swim is worth an injury or worse.
Never Swim Alone
It goes without saying, always swim with friends or your ‘pod.’ Swimming alone in open water carries significant risk, no matter how well you know the area or how accomplished you are as a swimmer. You never know when something can go wrong.
If you or a fellow swimmer is shivering, cold, or becoming disoriented, never let them swim back alone. If a swimmer is feeling great and wants to continue swimming, they don’t get to stay in alone either. Safety is in numbers to ensure everyone exits the water safely.
This applies to re-warming as well. Don’t simply get to the beach and send a person off to warm-up as this is when afterdrop and additional trouble can develop. Cold responses vary by individual, conditions, and timing.
Wear a Watch with a Timer
Knowing how long you’ve been in the water is crucial. If you planned for 45 minutes and you’re feeling great, stick to 45 minutes. Sometimes cold water can give us a feeling of euphoria right before we pass a tipping point into an unsafe zone. You can always add 5 or 10 minutes on your next swim.
If you planned for 30 minutes and feel a bit off at 15, get out.
Wearing a simple watch with a timer keeps you honest and within your limits. You don’t need anything fancy but you do need a timer. Cold brains forget what time you got in, exit plans, and simple math.
Winter Swimming Gear
After your swimsuit, cap, and goggles, the rest is up to you. Some choose to wear a wetsuit, booties, gloves, or a neoprene cap. Others stay ‘skin’ year-round and add an extra cap for warmth in the winter.
If you’re not using these already, consider adding them to your year-round gear list:
Earplugs: help keep you warm, avoid vertigo, and protect your hearing over time
Our pick - Mack’s Silicone EarplugsSwim Buoy (tow float): keeps you visible and can be an assist for yourself or a cold swimmer making it back to shore
Cap Light: shorter days mean you need to work harder to remain visible
Our pick - Guardian Expedition LED in green, blue, red, or amber.
No piece of gear prevents injury or guarantees safety. Equipment supports visibility and comfort, not protection from risk.
The Post-Swim Warm-Up Plan
Not everyone has access to a warm shower or sauna after a swim so plan your re-warming strategy before you get in the water.
Have your items ready in the order you’ll need them.
Re-Warming Kit
Towel (on top!)
Warm hat
Jug or thermos of warm water to rinse off
Changing robe or parka
Easy-to-pull-on-layers (hoodie, comfy pants - not leggings)
Warm socks
Easy-to-slip-on footwear
HotSnapZ Reusable Warmers (optional but a delight!)
Warm drink (tea, hot chocolate…)
Shivering is generally normal and your body's way of warming up. The sooner you get wet gear off and into dry layers, the better. And if you feel unsteady on your feet, sitting down right away may help.
Be sure and keep tabs on everyone in the group to make sure they are warming up. If you see someone struggling, give assistance. It may very well be you one day.
And the best final step to warming up? Take a walk and chat with your swim friends to catch up on life.
Disclaimer: This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Open water swimming involves inherent risks, including cold exposure, hypothermia, disorientation, injury, and death. Conditions vary by location, weather, and individual health. Further educate yourself about cold water swimming, its risks, and how to respond before participating. Consult a physician regarding cold water exposure and your personal health. Never disregard professional medical advice or delay seeking it because of information in this article. Never swim alone. Be aware of how you’re feeling and how others are behaving. Watch for signs of distress, hypothermia, or anything that seems off. Cold water conditions can become hazardous quickly if you’re uninformed, unaware, unprepared, or unhealthy. If something doesn’t feel right, stop swimming and exit the water immediately. Assess your condition. If symptoms persist or you believe your health is at risk, seek medical attention or call 911. You are responsible for your own decisions and should assess conditions, your experience, and your physical state before entering the water. Thanks for reading!