Rain or snow, live precipitation type

Over Rio del Mar, California, where the map opens. The whole country

What is falling at each place: rain, cold rain, snow, showers and storms, or rain with hail, every ten minutes. How to read it.

What the rain or snow map shows

What is falling at each place, as the radars and the air around them tell it: rain, cold rain falling through air near freezing, snow, the heavy showers and storms of a convective cloud, or rain with hail. Each place is drawn as one kind, never a blend.

How to read it

Rain: Steady rain.
Cold rain: Rain falling through air near freezing; it can freeze on roads and trees.
Snow: Snow.
Storms: Heavy showers and thunderstorms.
Hail: Rain with hail.

What it is for

See where rain turns to snow along a winter storm.
Find the cold rain that can glaze roads.
Tell steady rain from storms and hail at a glance.

How it is made

The storm analysis joins every radar in the national network every two minutes into one picture of the country on a grid about two thirds of a mile across, cleaned of ground clutter, birds and insects, and measures from it what no single radar shows: the largest hail, the turning of the wind, how high a storm’s heavy echo reaches above the freezing level, and what is falling, read with the temperature of the air. Storm Station keeps it every ten minutes for a day, the gauged rain and the radars’ view each hour, and draws it at every zoom from the analysis’s own grid.

A frame every 10 minutes, played as a loop of 1 to 24 hours. As data: /radar/now.json?show=ptype, the times of its frames.