If the swan has survived at the pond for 2-3 years, it has found a good habitat and is able to handle the inclement weather. Normally, 20-25 mph winds aren't that bad as long as there is no furniture or other objects from buildings that might get thrown into or across the pond. Even then, a 40+ mph wind would be of more concern.

Are there any trees surrounding the pond? Is the pond lower than the bank, i.e., sunken? Any of these factors will also provide some shelter from the wind. Additionally, swans will stay in the water and sleep/rest with their heads on their back. The birds' feathers shield their noses and face from the cold and wind.

Swans have large number of feathers including down which keeps them quite warm. As long as there is plenty of food and the pond does not freeze over, then the swan should do well. They can draw heat from the water as the water temperature is usually warmer than the outside temperature. Think of getting into a pool on a very cold day. Getting in and out is the problem. Once you are in the water, it actually feels quite warm. This would be the same for the swan.

You might ask the swan owner if he/she needs any swan food for the winter. This will help introduce yourself and offer some assistance if they are not providing food for the winter. The Regal Swan