Six reasons to do a full moon swim

Full Moon Swim

Full moon outdoor swimming is a thing, here’s why:

1. Rarity value

We only have 12 or 13 full moons in the year. They occur once every 29.5 days, roughly. If you live in the UK, there is a good chance the full moon will be hidden behind clouds. I have planned full moon swims before, only for it to be pouring with rain on the night. There are only a few occasions each year with the right combination of astronomical and weather conditions for a perfect moonlit swim. Some years you might not get any if the weather lets you down. A beautiful full moon swim is a special thing.

2. Aesthetics

Out on the water, it’s often darker than on land. There is less light pollution to spoil your view of the sky. The moon paints a shimmering glitter path across the water, and you can roll onto your back to look at the stars in comfort rather than straining your neck as you do on land. In winter, on a clear night, it’s easy to identify Orion’s belt, despite the brightness of the moon. Pictures don’t do it justice (and they often come out blurred — see above). You need to experience it.

3. It takes you out of your comfort zone

Swimming in natural bodies of water is already an intimidating experience. Add in the dark, cold if it’s winter, and an overactive imagination, and it becomes nerve-jangling. And that’s a good thing. Obviously, you need to ensure you take appropriate safety precautions (see below), but even when you’ve done that, and you know there is little danger, it’s still unnerving. Pushing yourself through those nerves is life-enhancing. It makes you feel tough, or at least a little smug.

4. Bragging rights

Clearly, by writing this, I’m guilty of exercising my bragging rights from my most recent full moon swim. I think I’ve earned it. It’s fun to hear people’s reactions. They run from: “are you sure you haven’t lost the plot,” to “that sounds amazing.” But really, it’s not like it’s any great achievement. It doesn’t take any special skills or talent. I haven’t trained for years to be able to do it. I’ve just got into the river, in the dark, and paddled about a bit, for about 10 minutes. Anyone can do it and I think everyone should.

5. Fun

Yes, it’s true. Getting into cold water, in the dark, is fun. Really! Perhaps because it’s plainly bonkers. Or maybe it’s the release of tension. I was nervous all day before my most recent full moon swim. Once you’re in the water, you realize your fears were exaggerated and that you’re privileged to live in a time and place that allows you to enjoy a special experience.

6. Enhanced senses

The Thames always has an odour. It’s not a bad smell — not usually, anyway — but it’s distinctive. Maybe there is a complex chemical reason that the aroma is stronger at night or because you can’t see so well, your sense of smell is enhanced. Either way, it’s noticeable. Secondly, you become hyper-alert to how you feel. Swimming in cold water does that anyway, but it’s stronger in the dark. It’s something of a cliché to say that outdoor swimming makes you feel more alive. I’m not sure what that means, but swimming in dark, cold water certainly tunes you into the present moment and your body, and all its connections to the world around you. It’s magic.


Winter wonder

Arguably, full moon swimming is better in the winter. In the summer, the full moon rises late. In June this year, the full moon on the 24th will rise at 21:37 (GMT) in London. Sunset that day is at 21:21 and civil twilight lasts until 22:09. If you want a full moon swim in the dark, you have to stay up late — and it never gets fully dark in June anyway. In contrast, February’s full moon rose at 17:46. Sunset was at 17:37 and civil twilight ended at 18:11. Obviously, the water will be warmer in the summer, but the moon and stars are brighter in the winter.

The next full moon is 28 March 2021. Lockdown restrictions in England are easing on 29 March. I think this means you can legally meet with five other people at a minute past midnight on 29 March for a full moon swim.

If you want to try a full moon swim, please remember that cold water plus darkness is a potentially fatal combination. Make sure you’re comfortable and competent to swim in cold water during daylight hours before trying it in the dark. Secondly, ensure you can be seen on the water. Some people fix glow sticks to their goggles or swimming costume. One thing that works brilliantly is to put a bicycle light inside a tow float (one of the ones with a built-in waterproof bag). The lights add to the fun and sense of adventure. Another tip, if you can, is to have a friend on the shore or bank with a bright torch to guide you back in and to light things up as you’re scrambling out.

Otherwise, follow all the usual outdoor swimming precautions (see the safety advice on Outdoor Swimmer’s website for details) and you’ll have a safe, enjoyable, and memorable experience.

Image: Richard Winter

01  Cover  April

Issue 48 April 2021

  • Revival! Celebrating our pools and lidos
  • The environmental impact of your swim kit
  • Top tips for returning to swimming after lockdown
  • How to find a wetsuit that fits
  • Legends of the selkies – the myths of underwater folk

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