Estimation on how cold will my pond get - intent is to know if certain fish can survive in it I want to get an estimate on how cold my pond will get.

It is a 1 acre pond in Central Florida USA. It has an average depth of 4 feet. There is not much circulation in the pond. It gets direct sunlight during these cold months. 

These are the average temperatures (high + low)/2 in Farenheit.

              °F       °C
November      65      18.3 
December      60      15.6
January       57.5    14.2
February      60      15.6
March         65.5    18.6


What is the warmest temperature the water will remain? Its not as simple as looking at the numbers and will take some judgement. The top half of the water will certainly be warmer than the bottom, and the 1 foot shallows near the bank will be even warmer due to the direct sun. 

The fish I am considering putting into this pond will have normal feeding behaviors recommended at 68 degrees but I estimate that it will go into conservation mode and not eat at around 60 degrees or possibly die.

Is it likely that the fish will be able to find water at or above 68 degrees during these months (on the bank or near the surface for the greater part of the day?) 

I don't have tools to measure the temperature of different parts of the water, and with the large amount of rain we have had lately the temp would be off.

Thank you for any insight.
I doubt a pond temperature will stay above 60 in central FL winter.Without circulation there will be large temperature gradients caused by stratification, especially on warm days. Surface plants probably lower the maximum temperatures. For such a large pond ,the relative humidity and wind will make a temperature difference ( evaporation is a major heat loss).  As a comparison , I have a small ( 1000 gal) pond with circulation and although our air temperatures are usually 98 -day and 76-night, I have never measured a temperature over 83 F and usually lower. So the water temperature is definitely lower than the average air temperature in summer. In winter I protect my pond from low temperatures but it gets to 52 F . However, tropical fish like danios, swordtails and mollies survive that temperature in pond conditions , although books will say such temperature will kill them . What fish do you plan to have ? With the history that FL has for raising tropical fish , I would think there would be information available , such as from the FL Dept of Agriculture.