Virginia snow and weather

Airport surface observations

70 instruments/minutes

temp, wind, gust, visibility, precip, pressure

The backbone. Individual sensors fail and the station does not, so every reading is published with the age of the observation beside it.

Data-collection platforms

25 instruments/hourly

temp, wind, gust, humidity, pressure

Shore stations, fire weather stations and river gauges on one identifier. Most of them measure the river and are never offered here; the ones that are published air temperature and wind. A platform that was quiet when the catalogue was built is still listed, because it remains registered with its network. It is the only shoreline wind this service carries.

Soil climate stations

3 instruments/hourly

temp, humidity, soil temp, soil moisture

Air and soil together: temperature and moisture measured in the ground at depth, hourly, mostly on farms and research land.

Climate reference stations

2 instruments/hourly

temp, humidity, wind, solar, precip

The national reference: triple sensors for temperature and precipitation, sited well away from buildings and paving, and kept to one standard across the country. The yardstick the other instruments are measured against.

Volunteer precipitation and snow observers

1,212 instruments/once a day

precip, snowfall, snow depth

The same measurement a cooperative observer makes, from many more gardens. Virginia publishes 1,212 of these against 96 cooperative observers, so on most days it is the densest picture of what is on the ground that exists.

Cooperative observers

96 instruments/once a day

snowfall, snow depth, precip, high, low

A person, a board and a ruler, in the morning. It cannot say what is falling right now and it is the best answer to how much is on the ground.