Sleet is a form of precipitation that occurs mainly during winter and spring when the temperatures reach freezing. Sleet occurs when snow flakes become denser due to rain drops that attach themselves to them. The density of sleet is therefore much less great and they are not as heavy as ice or rain, which consist totally of frozen water.

That is why sleet falls to the ground more slowly. Sleet has a diameter of 1 to 5 mm and does not pose a danger to people and animals; it does not dent cars. As sleet can primarily be expected during winter and spring it also does not pose a danger to fields and farmland.

When the diameter is less than one millimeter sleet is referred to as snow grains.

Sleet occurs when there is less moisture in the clouds making it impossible for hailstones to accumulate. One speaks of ice pellets when the temperature in the rain or storm clouds is less than -4° C and there are strong upwinds and downwinds.

Frequently rain is part of the situation, too, but the moisture is not enough to form larger pellets. One refers to little pellets that originally were snow as  snow sleet because they start to melt in the high clouds as a result of varying temperatures and then freeze again, whereby the snow crystals bunch up. Snow sleet can be mixed with snow.

Sleet is lighter than hail but heavier than snow. That is why sleet can cover streets half an inch thick within minutes during winter storms. Even if there is no ice the danger of slipping is greater. Therefore it is advisable to drive more carefully.

When temperatures are slightly above freezing the sleet melts quickly again so that the traffic disruption does not last for a very long time. The strong gusts of wind and the limited visibility that often accompany storms can also disrupt traffic, in addition to the severe sleet storm.

It is relatively difficult to predict sleet storms because precipitation around 0° C can fluctuate between snow, rain and sleet. It then depends on the temperatures and the content of moisture of the various layers of clouds which do not differ all that much from one another so that it is difficult to make an accurate prediction. It can also depend on the local conditions which can quickly cause a certain kind of precipitation. One should therefore expect  certain traffic restrictions and adjust one's way of driving accordingly.