I think @SkiJay and @Chris Rossi would say to move your bindings forward rather than back as the water warms up. Warmer water is less viscous (less drag) compared to cold water and as a result the tip of your ski rides higher and will not turn as well. Try moving your bindings forward assuming your fin has not moved.
Old article by @Chris Rossi as to what to do as the water cools, use the reverse for warming water.
Cold Water Ski Setup Recommendations
by Chris Rossi
Cold water does not ski the same as warm water. It is a fact that skiers have to deal with. It is no coincidence that when the hot summer months arrive, so does the good skiing. Warm water allows the ski to cast out for the buoy better, giving us more space before each buoy. The earlier you come into the buoy, the more time you have to make a balanced turn. This leads to less falls and more buoys completed. As the water cools down, we start to lose that space before the buoy and see a drastic reduction in buoy count. Lets take a look at changes we can make to help keep some of those buoys we tend to lose. I have listed the suggested changes in the order that I change them.
Move the Fin Back:
When distance from tail (DFT) is decreased, the tail of the ski slides out less in the pre turn. This helps to keep the ski out in front of the skier more. When the water cools down, the main thing I feel is that my ski wants to suck behind me much quicker after the edge change. This causes me to get too much of the ski in the water too early, taking away width and speed before the buoy. If I am too far forward coming into the ball, then I will have to rock back at the finish of the turn or I will blow the fin out and fall. By moving the fin back, more ski will be out in front of you in the pre turn, helping to set up the best turn possible. My general rule of thumb is to decrease DFT by 0. 003 inches for every 10 degrees of water temperature loss.
Make the Fin Deeper:
Fin depth controls ski stability. The deeper your fin, the more weight it will support on the edge of the ski. As the water cools, your ski feels like it rides higher in the water. This makes it feel much less stable. Add depth to give your ski back some of its support/hold. Another benefit of added depth is added width. Because the ski is able to run a little flatter in the pre turn, it will keep its speed and direction better. My general rule of thumb is to run the deepest fin possible. If you get too deep, the ski will not roll up on high enough edge angle to keep the direction you set out of the turn and you will run straight at the next buoy. Try adding 0.002 inches of depth per 10 degrees of water temperature loss.
The above-mentioned changes are my most common cold water fixes. Dial in these first and then use the following suggestions if more change is necessary.
Bindings Back:
By moving the bindings back, more ski can be kept out of water in the pre turn. This adds some space before the buoy and gives you more ski to finish the turn.
Less Wing:
Wing pulls the tip of your ski in the water. By reducing wing angle, you will delay the initiation of the pre turn, thus adding necessary width. Try 1 degree reduction for every 20-degree water change.
Reduce Length:
When length is taken out of the fin, the ski carries out farther before initiating the turn. This helps gain a little space before the buoy. Also, less length will allow the ski to make tighter turns on both sides. I don't tend to change my length settings too often regardless of temperature or location, but in extreme temperature changes (88 to 63 degrees) a length reduction of 0.005 inches has helped.