"George" wrote in message
.. .
snip
Don't know what the OP's pond is, above or below, mine is below ground.
But at
sometime someone tested the temp in their pond and there was a couple
degrees
difference. I'm too fond of my fireplace, my books and my warm labradors
to
experiment with this. Anyone out there want to experiment this winter??

Well, there you go. You've done and challanged me. I tried to do it last
year,
but didn't have the right thermometers for the job. I'll be doing it this
winter, and post the results. Remember though, that any results I get may
not
apply at a different latitude.

I am planning the same experiment. Shall we share notes/plans?

BV.