Thunderstorms in the region can be dangerous and damaging, bringing hail and high winds. In rare instances, they can bring a tornado. However, almost all summer rainfall in the city is brought by these storms. In spring and fall, longer events of prolonged, lighter rain bring most of the precipitation. A moderate snow cover can be seen on or linger for many winter days, but even during meteorological winter, on average, over 40% of days see less than 1 inch (2.5 cm) on the ground.