On Sunday, one of my kids was invited to swim in a friend’s in-ground pool.
In the early evening the friend stopped by and said they wouldn’t be swimming because his parents had forgotten to turn the heater on early enough, and the water was too cold. I asked “how cold is too cold?”, because it had been in the upper 90s all day, and I thought a cool dip might feel refreshing. He responded “63 degrees.”
Now I know water is slow to respond to changes in air temp, but I’m having difficulty in seeing how a pool could be this cold. It has been 90 or higer every day since at least the 4th, and I really doubt it has gotten below 70 any night. So how could the pool be 7 degrees cooler than the coldest air temp over the past week?
I also checked in the paper, and they say Lake Michigan (a slightly larger body of water than a pool) is in the 70s both at shore and at the offshore buoys.
Am I missing something obvious here, or was this kid just pulling some number out of his ass?
The only explanation I can think of is that they just filled it. The ground water could still be in the 50s or low 60s.
Other than that, I’m guessing it’s crap. We have a 30’ diameter aboveground pool up here in SE Wisconsin and our water temperature has been in the 80s with no pool heater at all.
Our water would come from Lake Mich instead of a well, and it generally stays pretty cool year round at the intake cribs.
But my wife suspected just this, and asked, “Do you change the water regularly?” and he responded “Every year!”
I wonder when the last time it was 63 degrees in Chi. I hear it was pleasantly cool - 70s-ish - weekend before last while I was out of town, but before that it was hot as blazes through most of June.
That’s a Spring-time temp and you’d be hard pressed to make your pool 63 degrees, even by adding water. He’s embellishing.
When it’s hot out, even 80-degree water can feel chilly, especially if the kid was spoiled by only swimming in a heated pool. When the pool temps reach 86-90, then it becomes very unlikely that anyone would call it cold.
But if the temp is 78-82, and it is hot out, it would not be surprising to find kids who think that is too cold for pool water.
Thanks.
I had no problem with his opinion that it was too cool for swimming. (Well, actually, as hot as it had been that day, I had difficulty imagining what would be too cold short of ice cubes!) I just had a bit of a problem with what struck me as an affirmative - uh - embellishment.
I was in Phoenix last weekend, and Denver this weekend. The hotel pool in Phoenix was quite warm in the morning (9AM), while the Denver pool was pretty darn frigid even at 6PM. I’m pretty sure it was 105 in Denver and 115 in Phoenix during the day. Not sure where I’m going with this, other than the thin atmosphere in Denver might have allowed the pool to cool much more there overnight than in Phoenix.
Spot on.
My pool is now in the 80s. In my house, only kids ever go in below 75, and the women in my family won’t even touch the pool unless it’s at least 80.
I have seen the temperature change ~4-5 degrees in a day, and that’s 18,000 gal, so unless the ground is extremely cool, I imagine that it would be very difficult to maintain a pool that cold.
What if it’s in the shade?
I had one of those pools that you inflate the top ring and fill it with water in my back yard, I think it was about 5000 gallons. I killed myself to warm that pool up. I had a solar cover to trap the little sun I could get, I ran the pump all day to keep it moving and at night I turned the pump. Even with enough with the warm days it never broke 70.
Man! Heating (and chlorine) is why I really hate pools – they feel like 300 kids have just pissed in them. Given the chance to swim in a pool with a broken heater is always fantastic. I grew up a five minute bicycle ride from Lake Huron, so what I consider chilly is potentially different from many folks.
Night time temps come into play, too. Accuweather.com shows recent temp trends. Denver, lows in the high 50s and low 60s. Phoenix, 70s and 80s as night time lows.
That’s a neat feature.
Shows the 1st 2 days of July had lows in the 50s and highs in the 70s. And tho highs have been above 83 since then, a couple of nights till got down to the 60s.
I wouldn’t have thought so.
I had to do a heat transfer problem in MatLab to find out how long a body had been dead, based on its temperature when found versus the ambient temperature (modeled as a sine wave, with one period per day). That’s when I realized I dug engineering. I may be able to dig the program up.
I believe he said 20K gallons, but that number might have been pulled out of his ass as well. Looks to me like a pretty good-size pool for a backyard (these folks have serious bucks).
My kid said she had seen the therm read in the 60s on other occasions, so she suspected they might have a faulty thermometer. Possible, I guess.
I so don’t get this! I used to swim at an unheated community pool every day when I was a kid in the 60s. It was a huge pool. I don’t see how 63 would be prohibitive (other than simple comfort…he said the water was too cold to swim in, which I took as a ‘danger’ thing). Nor do I see how it could be that cool after all the heat we’ve had.
FWIW, I used to date a guy with a decent-sized inground pool. It was situated in the yard so that it got quite a bit of shade from large pine trees. Even if it was hot and sunny out for a long stretch, the pool wasn’t really too warm unless he felt like heating it.
I may be able to dig the program up.