Winter wheat is a type of cereal that is planted from September to December in the Northern Hemisphere. Winter wheat sprouts before freezing occurs, then becomes dormant until the soil warms in the spring. Winter wheat needs a few weeks of cold before being able to flower, however persistent snow cover might be disadvantageous. It is ready to be harvested by early July. For winter wheat, the physiological stage of heading is delayed until the plant experiences vernalization, a period of 30 to 60 days of cold winter temperatures (0° to 5 °C).