How snowfall is measured, and why totals differ
Updated October 18, 2026. Live numbers refresh hourly.
Official snowfall is measured as the greatest depth of new snow on a white snowboard, read and cleared no more than once every six hours (four times a day), and totals differ because snow settles, melts and drifts and because nearby spots really do get different amounts. So far this season Denver, CO has about 0.0 inches against a 1991–2020 normal of 1.2 inches for the date.
- Soil today
- 61°F
- +3.8°F over 7 days
- Last 72 hours
- 0 in
- Snowfall estimate
- Season so far
- 0.0 in
- Normal by now 1.2 in
Live data for Denver, CO. Check your own ZIP below for local numbers.
The National Weather Service method
The National Weather Service's snow measurement guidelines ask observers to measure new snowfall on a snowboard, a flat board laid on the ground away from buildings and trees, and to take several measurements and average them where snow is uneven. The board is cleared after each observation. Clearing more often than every six hours would add up more snow than actually accumulated, because new snow settles as it sits, so the guidelines cap observations at four a day.
Snowfall (how much new snow fell) is different from snow depth (how much is on the ground). Depth is measured separately at a fixed time each day. A storm can drop 8 inches of snowfall yet leave 5 inches of depth by morning.
Why your yard doesn't match the report
- Settling and melting: snow compacts under its own weight, and warm ground melts it from below.
- Drifting: wind strips open areas and piles snow by fences and houses.
- Timing: a 24-hour total depends on when the day starts and ends.
- Real local differences: elevation, lake effect (see Buffalo lake-effect snow) and upslope winds can change totals sharply over a few miles.
Where our numbers come from
Our 24, 48 and 72-hour totals come from NOAA's National Snowfall Analysis, a gridded estimate at about 4 km that blends observations with model data, sampled at each ZIP and city center. Season totals come from daily reports at the nearest long-record station, compared with NOAA 1991–2020 normals. Both are estimates, which is why we say so on every page. Details are on how we measure.
If a contract or claim depends on inches, it needs an agreed measurement method. Our snow contract guide explains the options, and the Denver season guide shows how a season total is tracked.
Questions
How often is snowfall measured?
Under NWS guidelines, no more than four times in 24 hours, about every six hours, with the snowboard cleared after each measurement.
What's the difference between snowfall and snow depth?
Snowfall is new snow that fell during a period. Snow depth is the total snow on the ground at observation time, including older snow.
Why do snow totals vary so much in one city?
Elevation, wind, lake effect and storm track can change totals over a few miles, and settling and drifting affect any single measurement.
Sources
Soil temperatures: NOAA GFS model, 0–10 cm layer. Snow: NOAA and National Weather Service. See how we measure.