Open water swim temperature

The Pacific off San Diego is cold and choppy in the winter.  I've done a lot of running in January along Mission Beach, and there aren't that many people in the water other than surfers in surfing wetsuits.  A few hardy souls venturing in waist deep, mostly with families with kids, clearly on vacation from colder climates).  I don't recall ever seeing swimmers, nor there lifeguards. 

As for temperature, 60 is quite cold and I think many if not most people would use a full sleeve wetsuit and a neoprene cap.  I'm a cold water weenie, I don't train in 60 degree water unless that's going to be race day temperature.  For anything under 70, I use a full sleeve wetsuit.  For under 65, I add booties and a neoprene cap that covers my ears.  And I always use earplugs (Mac's pillow soft) in OWS, otherwise the cold water in my ears makes me dizzy as hell.

My last race was in the upper 60s and quite comfortable in a full sleeve.  Maybe a third of the field was in sleeveless, maybe 3 or 5 people without a wetsuit.  I recall doing an IM Boise 70.3 in the low 60s, everyone was in full sleeve wetsuits.

You could try it.  Beware rip tides, read the surf report.  Watch the surfers.  Be careful.

Some good advice right there.

It's swimmable, for sure (ocean stays cold here, but is painfully so all but 2 months a year and we get out in it), but not a lot of others around ups the risk factor a bit.  

Beware the "ice-cream headache," too.  Can take a little while to set in, and almost always passes within a few minutes, but if it hits you when you're getting tossed in any surf, it can be disorienting.  Only has hit me a couple times, and usually only when around 60 or below, but I wasn't expecting it (a really odd sensation when swimming rather than eating a slurpee).

Matt

I would recommend the sleeved suit and double swim cap if you don't have a neoprene cap.

Where I swim/surf (central coast of California) water temps around 60 is the norm, anything above is a luxury! During the summer/fall I was going for weekly OWS's in water that temperature. As mentioned, the initial cold will be a shock but you can get used to it. Pouring warm water down your wetsuit before getting to the water can help mitigate it.

60 = perfect OWS if you ask me.

Might be a little chilly at first but refreshing to say the least.