This is important for both weather forecasting and climatological purposes, because even precipitation amounts too small to be measured can have significant societal impacts.

[3] Meteorologists and other atmospheric scientists distinguish between a trace and zero accumulation in forecasts and climatological records for several reasons.

First, for accumulation of freezing rain and other icy precipitation, even a trace amount can result in hazardous conditions such as slippery roads.

[5] This can lead to unrealistic totals over time compared to the actual amount of snow that has fallen.

[6] In areas where imperial units are used (primarily the United States), liquid precipitation (rain and drizzle) is measured in intervals of 0.01 inches (0.25 mm), while snow, ice pellets, and most other precipitation types are measured in intervals of 0.1 inches (2.5 mm).