As a general rule, most grasses show disease problems when they are actively growing, not dormant. When the grass turns straw brown for the winter, it's that way for 6 months. A colder winter is better for the lawn. Cool season grasses can handle cold weather even if we don't get snow. But snow is a good thing, it will insulate the grass underneath. When we don't receive a lot of snow cover ,the grass can dry out in the winter time.... but Turf is a remarkable plant and will recover.
To help out we are asking homeowner's to keep their lawns mowed to a sturdy height of 1-1/2 - 2 inches ( 4-5 cm ) so the grass isn't TOO long when the snow falls. As the snow falls, it pushes the grass down and snow mold will develop to a greater degree. Also to rake up the leaves, or mulch them on top of the grass, but not to leave them as cover. If you do see pink or gray snow mold in the spring there isn't much you can do as prevention at this point. Just take a rake or fingers to break it up instead of leaving it to dry. If left, the snow mold will dry and glue the grass blades together, making it harder for new growth to pass that barrier. So rake the area and if too much damage is present, then top dress with some seed. Snow mold will fix itself with aeration and a little warm weather.
Red thread or leaf spot is common if the early spring is wet, or rust if the spring is dry. Good lawn care practices are the key to success. Mowing high, watering as needed, proper fertilization, core aerating, over seeding on a regular basis......those are all the things that are going to help you maintain a healthy lawn.