Rain-to-Snow Calculator

You can use this rain to snow calculator to compute the equivalent snow and the ratio of snow to rain per the air temperature and rainfall.

Rain-to-Snow Ratio

The rain-to-snow ratio varies according to multiple factors, including windchill, humidity, temperature, and precipitation.

According to the majority of weather services, the average level of snow is 10 times that of rainfall. As such, 1 inch of rainfall equates to around 10 inches of snowfall. In dense snowfall, the molecules are tightly compressed. In such situations, the rain-to-snow ratio will be 1:8. This ratio will fluctuate depending on the temperature and windchill. If the snowfall is light and more powder-like, the rain-to-snow ratio will vary between 1:20 and 1:50.

To use our rain-to-snow calculator, simply input the amount of rainfall in inches and the temperature in the unit of your choice. The calculator will compute the snowfall that can be expected in line with those weather conditions.

Rain-to-Snow Conversion

This calculator uses the following formula:

snow depth [inches] = rainfall [inches] ÷ rain-to-snow ratio

Let's look at an example of rain to snow conversion:

Let's say we wanted to determine the level of snowfall expected when the rainfall is 2.5 inches, and the temperature is at 12 °F. We would start by multiplying 2.5 by 30 (the reciprocal of the rain-to-snow ratio when the temperature is between 10 and 14 °F). This gives us 75 inches.

As such, when the rainfall is 2.5 inches and the temperature is 12 °F, the equivalent snowfall would be 75 inches.

*Note: Our estimate is based on rain-to-snow conversion tables from the NWS.