There was quite a bit of media interest, and the BBC have an article about it on their website (Swimmers brave cold for Lido dip). Similarly, a reporter from the Wandsworth Guardian wrote an article about this on Wednesday (Swimmers to brave the cold at Tooting Bec Lido), and she took part in one of the races today; I admire her for doing diligent research.
The lido is an open air pool, without any heating, so it's a bit chilly at this time of year: it was 3°C this morning, warming up to 4°C in the afternoon. (I put my hand in the pool, and it felt about the same as the water that comes out of a cold tap.) A less scientific approach is to observe how much people gasp when they enter the water (sample photo).
That brings up another issue: dress code. According to the rules, people weren't allowed to wear wetsuits, just normal swimsuits. This still allowed some variation, and there were a couple of guys in "mankinis" (as seen in Borat). Also, everyone had to wear a swimming cap, but in the breaststroke races the swimmers had to keep their eyes out of the water, so those races doubled up as "silly hat" contests. There are a few examples here, but my favourite was the guy who had a hat that looked like a duck. The best thing about it was that he had a dozen rubber ducks attached to the hat by strings, so they trailed along behind him in the water, like a mother duck being followed by all her ducklings.
So, I think it's fair to describe the swimmers as "eccentric". There was a sign up by the side of the pool:
There were a couple of guys providing a running commentary; I think that one of them was Alexander Armstrong. Anyway, they did a good job, and asked swimmers for comments as they left the pool (en route to the hot tub/sauna). A couple of quotes that stuck in my mind:
"It's almost better than sex!"
"I could cut ice with my nipples!"
The pool is very large: 100 yards (91 metres) long, and 33 yards (30 metres) wide. By contrast, most indoor pools are 25 metres long, and the one at my gym is only 20 metres. So, they set up six lanes across the width of the pool, and most of the races were just one width. They also had a few relay races, where people took it in turns to do one width each; at an indoor pool, people normally get into position early on, but today they waited until the last moment to slide into the cold water. Meanwhile, there was a separate section of the pool reserved for "dipping". The idea was that anyone could buy a ticket to go in there and just splash around without competing; the youngest person who did that was a 3 year old girl.
The races were divided up into age groups, and the oldest contestant was 86 years old; he's been doing outdoor swimming since 1934, which is pretty impressive. At the end of the day, there was an endurance event: five lengths of the pool, i.e. 455 metres. This wasn't a race, because it was enough of an achievement just to swim that far. One of the swimmers was 70 years old, and he did it in 11 minutes. This reminded me of a Guinness advert ("Good things come to those who wait"), where an old man does a swimming race in the sea each year (trying to get back to the pub before the barman finishes pouring his pint). These guys may slow down a bit as they get older, but I'd be happy if I could do the same thing when I'm their age!
It all looks quite fun, so I think I'll head back there sometime when I'm off duty. The Lido is closed for the winter at the moment (only open to club members), but it re-opens to the public on 23rd May. Based on what I've read, I think the best way to do cold water swimming is to start when it's relatively warm, then keep going; that's similar to what I've done with my cycling. I swam in the sea when I went to Cornwall (summer 2006), without a wetsuit, so it should be roughly the same temperature in London. After all, when I look at the other people who are doing it, I'll feel a bit feeble if I wimp out because it's too cold.
Anyway, all in all it was a good day out.