jobe's trip reports have temperature readings. Parents should know this, but generally 95-97ish is ideal for babies, with 90-100 being safe and comfortable. Anything much above that would likely be not ideal. No comment on the bacteria as that's always a danger. My parents used to take me before I could crawl to the sea and I used to play with the jelly fish, running around naked well into the years that followed along the shores of the Baltic Sea. Apparently I experienced overnight tent excursions when I was 6 months. Start them young. On the other side of the spectrum, definitely need to introduce them to double black diamond ski runs before the age of 4 or 5 for best results.