Assuming that the soil on which the turf is growing is well drained, the first thing that comes to mind is increased leaching. Leaching is the process in which water washes through the soil and takes various things along with it. In terms of turfgrass, what leaching water frequently takes with it is nitrogen. A winter of above normal rainfall can be expected to lower nitrogen levels in the soil. How much they are lowered is dependant on several factors including the clay and organic matter content of the soil, soil percolation rates, type of nitrogen fertilizer used and the timing of nitrogen applications.
Sandy soils leach more heavily than clay or high organic matter soils.
Slow release forms of nitrogen leach more slowly than water soluble forms of nitrogen. Lawns fertilized in the fall will have less nitrogen available this spring than lawns fertilized normally in the spring. Less mowing is one possibility. Poor color is another possibility. Increased incidence in disease is yet another possibility.