Weather for Lihue, HI. Overcast 69.6Â° Feels like 69.6Â° High: 79Â° Low: 72Â° Current conditions as of 04/21/17 5:40 AM HST. Humidity: 91% Visibility: 10.0 mi Dewpoint: 67Â° Barometer: 30.06 in Wind: SW Sunrise: 6:12 AM Sunset: 06:59 PM.
The American Concrete Institute recommends a maintained temperature of 70 degrees F for three days or 50 degrees F for five days to gain sufficient strength for a cold pour to perform up to specification.
I even did a Schmidt hammer test afterwards and the concrete was well above specs. I recommend insulating your pour anytime the weather will be below freezing. If it's between 0 and -10, than the heat from the cement should be enough to overcome the freezing temperature, but I would insulate anyway just in case.