Why do we close greens on some days during the winter?

The greens may be closed to protect the grass and soil structure if they are flooded (at any time of year) or if there is a frost.
During the winter the grass is less resilient due to fewer hours of daylight and more susceptible to disease. By reducing footfall on the greens during particularly stressful conditions (frost, excess water, etc.) we are preserving the health of the grass. Our policy is to protect the greens as best we can during the winter months so they are in better condition from spring onward.