In-water temperature gradient. What's the biggest delta you've experienced?

[miketsp]

I just got back from a weekend of diving at Ilha Grande in Brazil and experienced the highest temperature gradients I've ever seen.
Air temperature high 30'sC.
In-water near surface temperature 30C.
In-water at 20m, 15C in the cracks between the big rocks at the site Parcel do Coronel.
Similar range on the wreck Pinguino at 17m.

 

[archer1960]

It's not a big delta, but a very sharp gradient: 68F at the surface, 58F at 15' (5m).

 

[fjpatrum]

Surface temp ~ 58, 40 feet ~42 (Fahrenheit).

 

[tursiops]

One degree C per meter is not unusual.
(I'm an oceanographer)

 

[rhwestfall]

In my region (Great Lakes), and in my system of measurement, I have seen surface temps of as high as 75 degrees, with an "at depth" of 35 degrees....

thermocline typically at around 65'-70'

 

[Jax]

Depends on whether the upwelling happened during your dive.
78 at surface, was 74 at ~80 but this strange, shimmering water came at me . . . freaking 42!!!!

 

[wKkaY]

Barracuda Lake in Coron. 28C at the surface, 40C in the middle depths, and 28C again at the bottom

 

[TONY CHANEY]

Let's see: In NC during the summer at the quarry over 98 f at the surface and at about 26 feet 47 f. OTOH in Fla diving the caves, surface was in the 30's and the water temp was 72 f.

 

[archer1960]

And on the opposite side, there's when I was in Coz in 2014. 86F at the surface, and 86F at 102 ft.

 

[tstormdiver]

I've see air temps at nearly 100 degrees F, surface temps at 85 degrees F & below 50 ft, 42 degrees F (Have usually passed through 2 thermoclines). No matter the surface temp, below 50 ft in our local quarry, it is 42- 45 degrees.