A huge body of water does not change temp fast. If the sun is not shining or the wind blowing the water temp does not change at least not that fast. It would take weeks of air temp. changes to change the water temp because of the huge water volume. It changes very slowly. Also where we get most of our SW
fish and corals the temps never change. It stays the same temp all the time all year long. Places like Hawaii and other tropical places rarely change.
BTW a 1 or two degree change is not that bad. You dont want it anymore than that.