This graphic shows the annual balance between how much rain and snow a city gets on average each year. I’ve been wanting to make this graphic for a while, and have been holding out, hoping to find free gridded data for snowfall (the rainfall data are readily available). But I can’t find a free source, so I’ve given up and used city-level data instead. The city results are still interesting and reflect the interpolated snowfall data, a map of which is here:

http://www.climatesource.com/us/fact_sheets/fact_snowfall_us.html

A gridded rainfall map can be seen here: http://www.climatesource.com/cd1/fact_ppt_us.html

The data used for this graph are based on inches of rain and inches of snow. Keep in mind that an inch of snow is considerably less water than an inch of rain. I have not used water-equivalent snowfall here because the average density of the snow was not recorded (for good reason – it would be extremely difficult to keep track of it). So if it snows 50 inches in a city, and rains 30 inches, there may be a greater volume of water falling in the form of rain, but the city would appear to get more snow on this map. The scale is set to show how many times more inches of rain or snow occur in each city. So if it rains 50 inches and snows 25, the city gets 2x as much rain. Cities that get no snow are in the >6x as much rain group. Many cities get very little snow (or a lot of rain) and had far more than 6x as much rain, though the median of the dataset was near the balance point!

Data source: www.ncdc.noaa.gov/cdo-web/